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UNIVERSAL PORTLAND CEMENT CO. 



Copyright. 191 I 

by 

UNIVERSAL PORTLAND CEMENT CO. 

Chicago — Pitlsbutgh 



4-24-12 lOM 



Concrete Silos 

A BOOKLET OF PRACTICAL INFORMATION FOR THE 
FARMER AND THE RURAL CONTRACTOR 



trepared by the 

INFORMATION BUREAU 
UNIVERSAL PORTLAND CEMENi CO. 



Published by 

UNIVERSAL PORTLAND CEMENT CO. 
CHICAGO — PITTSBURGH 

Fourth Edition 
1912 



Table of Contents 

SILOS AND SILAGE h>^ Iv l/^ 

Definitions '...:'... 9 

The Theory of Silage. 1Q 

Silage Crops jO 

The Advantages of Silage. 10 

Dry Matter and Digestible Nutrients in Silage 12 

Efifect of Silage on the Flavor of Milk. 13 

Effect on Cattle of a Silage Ration 13 

CAPACITY, DIMENSIONS, AND LOCATION OF THE SILO 

Capacity for a Given Number of Cattle (Example ) 14 

Table of Capacities of Round Silos in Tons. 15 



Economical Diameter 



16 



Height. 16 

Location 17 

FILLING THE SILO— USING OFF SILAGE 

When to Harvest Ig 

Harvesting the Crop. Ig 

The Cutter Ig 

Elevating and Distributing. Ig 

Economy of Filling the Silo Rapidly 19 

Wetting the Silage. 19 

Cost of Filling 20 

Table Showing the Cost of Filling Fifty-nine Concrete Silos. 44 

Cost of Silage 21 

Using Off the Silage. 21 

ADVANTAGES OF CONCRETE AS A SILO MATERIAL 

Fireproof Construction 23 

George Pulling's Silo. ' 23 

A. B. Main's Silo 24 

The Element of Waste. 26 



The Effect of Free 



^i"g 26 



Concrete Silos in the South. 29 

WHAT IT COSTS TO BUILD A CONCRETE SILO 

Table showing the Cost of 78 Monolithic and 30 Block Silos 31 

Time Required to Construct Concrete Silos. 33 

A Comparison of the Monolithic and Block Types 33 

BUILDING THE SILO 

Contract Work o . 

Work Under Hired Foreman. 34 

Work Under Home Supervision 35 

Co-operation in Silo Work. 35 

FOUNDATIONS 

Laying Out the Work 3g 

Excavating. y- 

Placing the Concrete 3^ 

Imbedding Reinforcing Rods. 36 

Table of Materials for the Footings and Floor ^7 



gCI.A3J54Gl 



UNIVERSAL PORTLAND CEM E NT CO. 5 

MONOLITHIC SILOS 

Definition of "Monolithic" 39 

HOME MADE SILO FORMS 

Description of Forms 39 

Table of Materials for Forms. 43 

Cost 43 

Care in Bracing Supports. 43 

Importance of a Smooth Wall 43 

Painting the P'orms. 46 

DOORWAYS 

Continuous Doorways 46 

Frames and Doors. 46 

Erecting and Anchoring Frames 47 

Non-continuous Doorways. 47 

Doorway Form and Frame 48 

Doors. 49 

CONSTRUCTING THE SILO WALLS 

Tables of Materials 51 

Moving Up Forms for the Next Course. 51 

Height of Wall at Each Filling 54 

Labor Required. 54 

Reinforcing 54 

Spacing of Rods — P^xample. 54 

Reinforcing Tables 54 

Purchasing Reinforcing Rods. 54 

Hoisting Materials 55 

COMMERCIAL MONOLITHIC SILO SYSTEMS 

Polk System 57 

New Enterprise System. 58 

Angevine System 59 

C. A. Anderson's Forms 60 

McCoy Forms 61 

CONCRETE BLOCK SILOS 

Popularity of Hollow Concrete Blocks. 62 

Examining Blocks. 62 

Laying the Blocks 62 

The Mortar. 63 

Reinforcing— Example 63 

Reinforcing Tables. 64 

Table of Blocks Required 65 

Recesses for Reinforcing Rod. 66 

Continuous Door Frames 66 

Doors. 66 

HOME MADE BLOCKS 

List of Block Machine Manufacturers 68 

Home Made Mold. 69 

Size of Block 69 



6 CONCRETE SILOS 

COMMERCIAL CONCRETE BLOCK SILOS 

The Perfect Silo 70 

The Zeeland Silo. 72 

THE CHUTE 

Size of Chute 73 

Foundation. 73 

Monolithic Chutes 73 

Block Chutes. 73 

WATER SUPPLY TANK 

Size of Tank 1(i 

Planning for the Tank. Id 

Reinforcing Diagram _ 11 

Table of Capacities of Tanks. 11 

The Floor 78 

Table of Materials for the Floor. 78 

Continuing Walls Above the Floor 79 

Reinforcing — Fxample. 80 

Piping and Overflow 80 

THE CONCRETE ROOF 

The Cornice 81 

Roof Framing. 82 

Placing the Reinforcing 82 

Concreting. 84 

Table of Materials 85 

Monolithic Roofs for Hollow Block Silos. 85 

INDEX TO TABLES 

Table Title Page 

A Dry Matter and Digestible Nutrients in Silage. 12 
B Quantity of Silage Required and Economical Diameter for 

the Dairy Herd. 14 

C Capacity of Round Silos in Tons. 15 

D Cost of Filling 59 Concrete Silos. 44-45 

E Cost of 78 Monolithic Concrete Silos. 31 

F Cost of 30 Concrete Block Silos. 32 

G Materials for Silo Footings and Floors. 37 

H Materials for Home Made Silo Forms. 43 

I Cubic Yards of Concrete in Silo Walls. 51 

J Cement, Sand and Gravel Required for Silo \\'alls. 52 
K Size and Spacing of Reinforcing Rods in Monolithic Silo 

Walls. ^ ^ 53 

L Block Required for Walls of a Concrete Block Silo. 64 

M Size of Reinforcing Rods for Concrete Block Silo. 65 

N Capacities of Water Supply Tanks. 77 

O Materials and Reinforcing for Tank Floors. 78 



IN preparin.q- data for this booklet, the Information Bureau of the 
Universal Portland Cement Company investigated during- the Spring' 
of 1911, one hundred and ten monolithie and bloek silos loeated 
in the North Central States. Methods of silo construction and opera- 
tion were carefully studied and data on the actual cost and labor 
required, and other important information was obtained. Valuable 
assistance was received from a number of sources, particularly from 
the bulletins of the Department of Agriculture and the State Experi- 
ment Stations, several paragraphs from which have been used ver- 
batim. 

The reader seeking further information on the subject of silage 
and silo construction will find in the following pamphlets a compre- 
hensive course of instruction : 

Cement Silos — Farmers' Bulletin No. 405, U. S. Department of Agri- 
culture. 
Silos and Silage — Farmers' Bulletin No. 32, U. S. Department of 

Agriculture. 
Cost of Filling Silos — Farmers' Bulletin No. 292 U. S. Department 
of Agriculture. 

Concrete Silo Construction — Bulletin No. 214, University of Wis- 
consin, Madison, Wis. 

Cement Silos in Michigan — Bulletin No. 255, Michigan State Experi- 
ment Station, East Lansing, Michigan. 

Silage and the Construction of Modern Silos — Bulletin No. 83, Wis- 
consin Agricultural Experiment Station, Madison, Wisconsin. 

The Silo— Monthly Bulletin No. 2, Volume 6, Missouri State Board 
of Agriculture, Columbia, Missouri. 

The Reinforced Concrete Silo — Circular No. 49, by the Missouri Agri- 
cultural Experiment Station, Columbia, Mo. 

Silage and Silo Construction — Bulletin No. 4, Vol. II, Kansas State 
Agricultural College, Manhattan, Kansas. 

Silos and Silage in Maryland — Bulletin No. 129, Maryland Agricul- 
tural Experiment Station, College Park, Maryland. 

The Silo and Silage in Indiana — Bulletin No. 40, Purdue Agricultural 
Experiment Station, LaFayette, Indiana. 

Soiling Crops, Silage and Roots — Bulletin No. 9, Series II, College of 
Agriculture, Cornell University, Ithaca, New York. 
(Farmers' Bulletins published by the Department of Agriculture 

may be obtained by addressing Joseph A. Arnold, Editcr-in-Chief, 

Bureau of Publications, Department of xA-griculture, Washington, 

D. C.) 

In addition to the publications mentioned above, "iModern Silage 
Methods," published by the Silver Manufacturing Company, of 
Salem, Ohio, contains much valuable information which the silo 
builder and farmer should have. 



For the information of parties planning the erec- 
tion of concrete silos, we quote the following from the 
opinion of our patent counsel relative to the Harder 
patent No. 627732. 



"The Harder patent as interpreted by Jiid^e Ray 
is limited to a silo having a continuous opening from 
top to bottom, a series of sliding doors, reintorcing 
strips and braces of peculiar form. The court said 
in its cpiniDn, 'It is obvious that the braces of the 
Harder patent would be superfluous in stone or 
brick silos'; this being true, the Harder improve- 
ment would be wholly unnecessary in silos made 
of concrete. 

Therefore we advise you that the Harder patent 
does not cover all forms of silos; that it is limited 
and restricted to substantially the exact construction 
which it shows and describes and that it is unneces- 
sary, if not undesirable, in silos made of concrete." 



Since concrete silos are not covered by the Har- 
der patent, farmers and contractors need have no hes- 
itancy in building silos of concrete and are requested 
to advise the Universal Portland Cement Company 
of cases where any claim of an infringement is made. 



UNIVERSAL PORTLAND CEMENT CO- 



Concrete Silos 



Silos and Silage 

HISTORY will record the Nineteenth Century as an era of un- 
precedented agricultural progress. During the first fifty years 
the steel plow, the cultivator, and the harvester came into use, 
and succeeding decades brought the tractor, the gasoline engine, the 
great irrigation and dry farming projects and the silo — the latter 
destined to become one of the most 

potent factors in American farm ' 

economy. 

Conservation is the watchword 
of the present century. With the 
farmer the question is not only 
"How much corn can I raise?" but 
also "How can I get the most out 
of my corn?" * * * It is this 
spirit which has dotted the dairy 
and stockraising sections of the 
country with silos, from Maine to 
Oregon, and from the Gulf to the 
Canadian Provinces, until, as a re- 
cent writer has put it, "A good dairy 
community can be judged by the 
number of silos on the horizon just 
as an oil district may be known by 
the luimber of derricks in use." 

The silo is one of the true con- 
servators of the nation's resources. 
Several state experiment stations 
have estimated that 40 per cent of 
the value of corn is in the stalks, al- 
most all of which is saved if the lat- 
ter are placed in a silo. When other 
crops are used the saving is almost 
as great. The results have enabled stock and dairy men to keep more 
cattle on the same sized farms, as well as to maintain the herds in 
better health, and increase the milk flow. Several Southern Michigan 
farmers keep 20 head of dairy cattle on 20 to 30 acres by feeding 
them from the silo all year round, and having but small pastures. 
In such cases silage has been found equal to June grass, and entirely 
without harmful effect, even when used 365 days out of the year. 

Definitions: — The silo is an air-tight chamber or tank often 
wholly above ground, but very frequently having as much as one-third 
of its capacity below the surface. In its original form the silo was 
merely a large pit, being entirely below ground. The function of the 




Fig. 1. Two 60-foot Polk silos, being con- 
structed for Mr. Petei Emge, Fort Branch, 
Ind., showing forms in position for last 
filling. 



10 



CONCRETE SILOS 




Fig. 2. J. C. Eastman's concrete silo. Crown 
Point, Ind. Height, 41 feet; Diameter, 18 
feet. Capacity. 238 tons. N. L. Smith, Crown 
Point, architect. 



silo is to preserve green succulent food which is thus available during 
summer droughts when pastures are used up, and during the winter 
when dry feed alone results in shrinking milk flows and checked 
growth in fattening stock. 

The term "ensilage," or more 
properly "silag-e," is used to denote 
the fodder preserved in the silo. 
In the corn belt States silage is 
usually made from corn, while in 
other parts of the country sorghum, 
pea vines, alfalfa, clover, soy beans 
and cow peas, supplement corn to 
a considerable extent, or are some- 
times substituted for it. 

The Theory of Silage :— Silage 
is kept in the silo very much as 
fruit, vegetables and other articles 
of human food are preserved in air- 
tight cans. The germs which cause 
fermentation can grow only when 
supplied with oxygen, and if air is 
kept from the silage it can be pre- 
served for an indefinite period. As 
soon as the silo is filled, fermenta- 
tion begins, continuing until the 
supply of oxygen is exhausted. If 
the silage is well packed, and neither too green nor too ripe, it will con- 
tinue the ferment for but a short time, and will be practically uniform 
below the top coating. The sweetness of the food depends upon the 
stage to which the fermentation was carried, and the subsequent exclu- 
sion of air. Sour silage is not as wholesome as sweet silage nor will 
the cattle partake of it so freely. The best silage can only be made 
in a practically air-tight silo. 

_ Silage Crops:— Corn is undoubtedly the best silage crop wherever 
It will grow to full maturity. The yield per acre is heavy, the losses 
small, and the cost of harvesting lower than for most other crops. 
Sweet corn is not as desirable for silage because the sugar tends to 
produce excessive acid. Sweet sorghums are objectionable for the 
same reason, but those of the non-saccharine or kaffir-corn variety 
make good silage and will undoubtedly be used largely in the semi- 
arid portions of the southwest, where sorghum is a better crop than 
corn. Alfalfa and clover both make good silage but are little used as 
yet. Pea vines are commonly used where they can be obtained as 
a cannery by-product, and make excellent silage when mixed or used 
in conjunction with corn. 

The Advantages of Silage :— Someone has compared the difference 
between silage and dry feed to that "between a juicv, ripe apple and 
the green dried fruit." Because of its succulence, silage has a beneficial 
ettect on the digestion of the animals and they become very fond of il 
Ihe economy of storing silage is a feature which appeals at once to 



UNIVERSAL PORTLAND CEMENT CO. 



11 



the average farmer. Two and one-half to three tons of silage is 
eauivS in feeding value to a ton of hay and may be stored in 
one half to two-thirds the space occupied by the latter As already 
mentToned in a previous paragraph, more cattle can be kept on a 
glen amount of land with silage and there is the additional advan- 
tao-e that after the crop is in the silo 
the feeder is not dependent to any 
extent whatever upon weather con- 
ditions. The Missouri Farmers 
Bulletin No. 11 sums up the advan- 
tage of silage as follows: 
L Silage keeps young stock thrifty 
and growing all winter. 

2. It produces fat beef more chea])- 
ly than does dry feed. 

3. It enables cows to produce milk 
and butter more economically. 

4. Silage is more conveniently 
handled than dry fodder. 

5. The silo prevents waste of corn 
stalks, which contain about one- 
third the food value of the entire 
crop. 

6. There are no aggravating corn 
stalks in the manure when silage 
is fed. 

7. The silo will make palatable 
food of stuff that would not 
otherwise be eaten. 

8. It enables a large number of ani- 
mals to be maintained on a given 
number of acres. 

9. It enables the farmer to preserve food which matures at a rainy 
time of the year, when drying would be next to impossible. 

10. It is the most economical method of supplying food for the stock 
during the hot, dry periods in summer, when the pasture is short. 
In a recent circular, Mr. Chris De Jonge, of Zeeland, Michigan, 
has written the following as an example of concrete silo economy : 

"You can grow only two tons of hay on one acre and ten tons of 
ensilage on the same acre. Two tons of hay at $12.00 per ton will bring 
$24 00 Ten tons of ensilage at $4.00 will bring $40.00. That is 
$16 00 per acre in favor of the ensilage. One ton of hay will cost 
$1 50 to cut and bring into the barn, and one ton of ensilage will 
cost only 60 cents to cut and put in the silo. If you feed one cow 
40 pounds of ensilage per dav, it takes nearly eight tons to feed her 
one year. So if you only get eight tons of ensilage per acre you can 
feed one cow one year from it, or two cows one-half year off one 
acre If you pasture your cows during the summer, six months, it 
takes two acres to pasture one cow. ^ So by having a silo you keep 
four times as many cows as you do without a silo. 




Fig. 3. Monolithic silo, nearly completed 
by the Polli-Genung-Polk system, on 
tlie farm of John Creighton, Geneva, 111. 
W. H. Warford, Contractor. 



12 



CONCRETE SILOS 



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UNIVERSAL PORTLAND CEMENT CO. 



13 



"If you have ensilage to feed, you can keep your cow for 10 cents 
per day less than without ensilage. So if you get 10 cents for 200 
days for one cow it amounts to $20.00. Then if you have ten cows 
your gain is $200.00, for which you can buy a concrete silo and pay 
for it in one year." 




Effedls of Silage on the Flavor of Milk 

Prof. W. J. Eraser, of tlie Illi- 
nois Experiment Station, recently 
made some interesting observations ^ 

on the effect of silage on the flavor 
and odor of milk. The dairy herd at 
the University was divided into two 
lots, one of which was fed 40 pounds 
of corn ensilage per cow daily, while 
the other was fed only clover, hay 
and grain. The milk from each lot 
was standardized to 4 per cent and 
otherwise cared for in exactly the 
same manner. Samples from each 
lot sent to milk experts in experi- 
ments were submitted to 2i72 per- 
sons for an opinion as to any differ- 
ence in the flavor of the two sam- 
ples, anything objectionable about 
either, and any preference. The re- 
sults showed that 60 per cent pre- 
ferred silage milk, 29 per cent non- 
silage milk and 11 per cent had no 
choice. When the silage was fed 
at the time of milking, the percent- 
age in favor of silage milk was much higher than when the silage was 
fed one hour before milking. Five samples of each lot were sent to 
milk experts in different cities, three of whom preferred silage milk, 
one non-silage, and one had no choice. No complaint was received 
from a hotel to which silage milk was delivered for a period of one 
month. On the whole it was apparent that the greater number of 
people were able to distinguish between the two kinds of milk, but 
found nothing objectionable al)nut either kind. 

The Effedl on Cows of a Silage Ration* 

During the winter and spring of 1904 the Ohio Experiment Sta- 
tion conducted an experiment with ten dairy cows, representing five 
different breeds, "to determine what effect the feeding of more silage 
than is usually fed by dairymen, with a corresponding reduction in 
the grain portion of the ration, might have upon the production of 
milk, butter fat, gain in live weight, cost of ration and consequent 
profit." 



i 



Fijj. 4. Concrete block silo on estate of E. 
Evenson. Litchfield. Minn. ni;imeter, 14 
feet ; height, 32 feet. Cost, S.<12.00. 



•From Farmers' Bulletins No. 267. 222. 



14 



CONCRETE SILOS 



The cows fed on the silage ration produced 96.7 pounds of milk 
and 5.08 pounds of butter fat, while those fed on the grain ration pro- 
duced 81.3 pounds of milk and 3.9 pounds of butter fat, on an equiva- 
lent amount of feed. 

The cost of feed per hundred pounds of milk was $0,687 with the 
silage ration and $1,055 with the 
grain ration. The cost of feed per 
pound of Ijutter fat was 13.1 cents 
witli the silage ration and 22.1 cents 
with the grain ration. The average 
net profit per cow per month (over 
cost of feed) was $5,864 with the 
silage ration and $2,465 with the 
grain ration. 

Capacity and Dimensions 




—The capacity of the 
upon the number of 



Fig. 5. Lewis McNutt's monolithic silo, 
Brazil, Ind., showing cutter and blower in 
position, ready for filling. 



Capacity 

silo depends 

cattle to be fed, and the length of 
time that silage is required. This 
period usually lasts from 180 to -240 
days, although very frequently silage 
is fed almost the entire year. The 
following table shows the approxi- 
mate amount of silage required to 
feed 8 to 100 dairy cows 180 and 
240 days, based on a daily consump- 
tion of 40 pounds of silage per head. 





TABLE B. 




Quantity of Silage 


Required, and Economical Diameter of 
Herd. 


Silo for the Dairy 


Number of 


Feed for Feed for 


Diameter 


Dairy Cows 


180 Days 240 Days 


of Silo 


8 


29 tons 


40 tons 


8 ft. 


10 


36 •' 


48 " 


10 " 


15 


.S4 '■ 


72 " 


10 " 


20 


72 " 


96 " 


12 " 


25 


90 '• 


120 " 


14 " 


30 


108 '■ 


144 " 


16 " 


35 


126 " 


168 " 


16 " 


40 


144 " 


192 " 


18 " 


45 


162 •• 


216 " 


18 " 


SO 


180 '• 


240 " 


20 " 


60 


216 '• 


288 " 


22 " 


70 


252 " 


336 " 


22 " 


80 


288 "■ 


384 " 


22 " 


90 


324 '• 


*432 " 


22 '• 


100 


360 " 


*480 " 


22 " 



*Where more than 400 tons of silage are required, the use of two silos is 
generally advisable. 



UNIVERSAL PORTLAND CEMENT CO. 



15 






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16 CONCRETE SILOS 



Diameter: — After determining the approximate amount of silage 
required, the most economical diameter for the silo must be decided 
on. The diameter should depend upon the number of cattle to be 
fed, and at least 2 inches of silage must be removed each day to pre- 
vent spoiling. The diameter required for various numbers of cows 
is about as given in the two right columns of table "B." Dairy cows 
eat from 30 to 40 pounds of silage per day, which amount equals about 
one cubic foot. Horses and mules eat about one-half and sheep about 
one-third as much as cows. 

Height: — The height of the silo must be such that the reciuired ca- 
pacity may be obtained with the most economical diameter, providing-, 
however, that the height does not run above 40 feet for the small dia- 
meters, and 50 feet for the large diameters, according to the limitations 
of table "C." Extremely high silos are not as accessible and are more 
difficult to, fill than less lofty structures. For these reasons two silos 
are often preferred. The high silo of small diameter has less waste 
than the silo of larger diameter, and the greater weight of silage in 
high silos reduces the amount of trampingnecessary and silos of smaller 
diameter allow greater variation in the size of the herd without loss 
from spoiling of silage. 

Example: — Required, a silo of sufficient capacity to feed 30 cows 
for a period of 180 days. Referring to table "R." run down the ver- 






i 



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Fig. 6. Coiurirf iilotk silo -.inc) fv.irn of Thomas Coyne, nonr Fond riti I.nc, Wis. The silo is 
con^rurted of Coynt 's double-wall hollow blocks. It is 14 feet in diameter by 30 feet in 
height, and coSt $350.00. 



UNIVERSAL PORTLAND CEMENT CO. 



17 



Wl 



tical column headed "Number of Dairy Cows" to 30. Run- 
ning across horizontally, it will be seen that for 180 days' feed, 108 
tons of silage will be needed, and that for a silo of this capacity, the 
diameter should be 16 feet. Referring to table "C," run down the 
column headed "16 feet" to the numbers nearest the estimated capac- 
ity (108 tons). For a 16-foot silo of 109 tons capacity the height wall 
be 28 feet. 

Location 

LOCATION: — The silo should be placed where it will be con- 
venient for filling, and if possible, where the ground is firm, so 
there will be no danger of settlement. Silage is heavy feed, 
and therefore an unhandy arrangement with respect to the feeding 
alley always greatly increases the work connected with feeding. One 
of the best arrangements for con- . 
venient feeding is to place the silo 
or silos at the end of the alley. If 
this be done, a silage car can be 
used to advantage without having 
sharp corners to turn. The silo 
should not be surrounded by Iniild- 
ings and pens in such a way as to 
interfere with filling. Obstructions 
hinder the work greatly, increasing 
the cost to the owner. 

In most cases where the ground 
is soft, it will pay to carry the foun- 
dation down to a firm bottom, or to 
fill in with gravel. If it is impracti- 
cal to go down to solid earth, the 
footings must be increased to at 
least twice the breadth recom- 
mended on page 36, and more if 
there is the least uncertainty. 

In parts of the country where 
winters are severe, there is an ad- 
vantage in placing the silo on the 

south side of the barn, where it will be protected from the north winds. 
In the past quite a large number of silos have been built within the 
barn, but this practice is not recommended for several reasons. Such 
silos are inconvenient to fill, and silo odors are objectionable in the 
barn, for unless great caution is taken, the milk is apt to be con- 
taminated. 

Perhaps the most common fault made in locating silos is to get 
them too far away from the barn. In cases where this distance is 
made too great, the only way of remedying the situation is to build 
a room connecting the silo with the barn, thus incurring needless 
expense and increasing the distance to haul the silage. The distance 
from silo doors to barn need never be over 4 feet, which is sufficient 
for ^ chute of the ordinary size, 



g 

P 



Fig. 7. Monolithic silo of Hugh Ferguson, 
near Rockford. Illinois, with concretechute 
and roof. Diameter, 14 feet; height. 4.=) feet. 
One of several similar silos consl^rucfted 
by Edward Kuharske, Rockford, Illinois. 



18 



CONCRETE SILOS 




Filling the Silo 

WHEN TO HARVEST:— The corn should be cut while the 
stalks are still green, but after the lower leaves have begun 
to dry. xA.t this stage the kernels have hardened or "glazed" 

on the outside, but are yet in the "dough" condition in the middle. 

If cut too green the silage will lack protein, sugar and other nutritive 

elements, and will contain an excess 
of moisture, generally making it 
sour. If too matured, it will be dry 
and unpalatable, with the fibre very 
prominent. In this condition it con- 
tains less nutriment, is relished less 
by the cattle, and is apt to mold or 
"fire-fang," causing it to be greatly 
damaged. Corn dried out in the 
shock makes poor silage unless wet 
when put into the silo. 

Harvesting the Crop: — The 

har\esting of corn or sorghum for 
the silo may be done by hand with 
the ordinary- corn knife, but the corn 
harvester or binder is the imple- 
ment almost universally used for 
this work. In some sections of the 
country corn has been cut with a 
sled equipped with saw-like knives 
projecting from both sides, but this 

V used to any great extent. Except 
1)a(lly, as was the case in some sec- 

liuder can be uscfl to ad\antage. It 



r 



Fig. 8. Moil jlithic silo 


on 1,. A. ( 


L.i;.ul<Mll 


farm, Walworth, Wis. 


Capacity, 


114 tons; 


cost, $325.00. 







meth(_)d of har\-esting is not tn 
where the corn has fallen dowi 
tions of Michigan in I'MO, the 



e in cutting the cro|), bnt also binds it into bundles 
i> load on the wagon and feed into the cutter than 



not only saves tin 
which are easier t 
the loose corn. 

The Cutter: — Corn is sometimes placed in the silo uncut, but this 
practice is not to be recommended because the stalks will not pack 
closely, and the resulting air spaces cause excessive fermentation. 
The material is not as easily handled as cut silage, nor is it as eco- 
nomical to feed. The crop must be cut up fine for best results and 
when corn is used the entire plant, including ears, should be fed into 
the cutter. Although practice varies greatly, it is safe to say that 
corn for the silo should be cut one-half inch or even shorter. It is 
a well-known fact that corn will pack better in the silo the shorter 
it is cut, increasing the capacity to a considerable extent. Cattle 
like short silage better and will eat it up cleaner. 

Elevating and Distributing: — From the cutter the silage is ele- 
vated by a blower or conveyor, and deposited in a chute or automatic 
distributer. One or two mcii are required within the silo while it is 



UNIVERSAL PORTLAND CEMENT CO. 



19 




being filled, to tramp down the sides close to the walls, and to keep 

it leveled off (thus preventing the formation of air pockets), and to 

mix the heavier portion of the silage with the lighter. Silage 

has a tendency to cling to the sides of the silo unless well tramped, 

and the heavier particles roll to the edges while the lighter remain 

near the discharge. The automatic 

distributer greatly simplifies the 

work of filling the silo and does 

away with much of the tramping. 

The operator is simply required to 

guide the mouth of the tube, and 

the material descends with sufficient 

force to pack it nicely, making a 

minimum amount of tramping nec- 

essar3^ 

Economy of Filling the Silo 
Rapidly: — It is common practice to 
fill the silo as rapidly as possible, 
that is, keeping the cutter and 
blower busy continually. This is 
the only economical method where 
the engine and cutter are rented, or 
hired labor depended upon. How- 
ever, if these considerations do not 
enter in, there is no objection to fill- 
ing the silo gradually, so long as 
fresh silage is put in before mold is 
formed on the surface of that previously placed. In rapid filling, a 
day or two should be allowed for settling, and the silo filled up a 
second and perhaps a third time in order to utilize all of the space. 

During the process of filling all doors above the height of the 
silage should be left open for the purpose of letting out the carbonic 
acid gas which is given off. 

Wetting the Silage: — When the filling is finally completed, the 
top should be wet down at the rate of about one gallon of water per 
square foot of surface, and thoroughly tramped. This aids greatly 
in compacting the silage near the top, reducing the depth of the 
spoiled material on the surface. In many communities it is a practice 
to run in a quantity of straw or chaff after finishing with the silage, 
and then planting oats or other small grain. Where this is done there 
is seldom any loss of silage worth mentioning, and the growth on top 
is generally fed to the cattle. 

Cost of FiLing : — Condition of crop, length of haul from the field 
to the silo, size of silo, method of harvesting- and the cost and arrange- 
ment of labor are all elements which affect the cost of filling a silo. 
Farmers' Bulletin No. 292, Department of Agriculture, says: "In 
many cases a poor arrangement of help is responsible for extra ex- 
pense. It is not necessary for men and teams to be rushed to their full- 



'» Monolithic silo of Howard and Syl- 
\ f stcr 1 honipsori. Rose Creek, Minn. The 
first silo in Mower county Cost, complete, 
$214; capacity, W tons. Work done by men 
without previous experience in concrete 
work, with local materials. Silo has stood 
five years, and shows no cracks nor checks. 



20 



CONCRETE SILOS 



est extent in order to get the work done cheaply. Some of the most 
expensive work was conducted with the greatest furore and hurry. The 
scheme where all are working and no one is hindered by the others, is 
the most economical. 

The table on pages 44 and 45 shows the cost of filling 59 concrete silos 
during the season of 1910. Although 
the location of the various silos is 
not set down in this table, this in- 
formation may be found by compar- 
ing the numbers of the silos with 
those given in the tables on pages 
31 and 32. Almost without excep- 
tion the figures contained in these 
tables are considerably higher than 
usual, due to a poor crop of corn in 
most sections touched by the inves- 
tigation and also to the peculiar 
ci^ndition of the crop in some sec- 
tions of Michigan, where it fell down 
so badly as to make the use of har- 
vesters impossible. 

See Table D, Pages 44 and 45. 
The average cost of filling 16 
concrete silos in Illinois was found 
to be 572 cents per ton; average 
of 22 silos in Michigan, 64 cents 
per ton ; average ot 10 silos in Wis- 
consin, 57 cents per ton; average 
of 4 Minnesota silos, 71 cents per ton ; of 2 Ohio silos, 89 cents per 
ton; and of 2 Missouri silos, 50 cents per ton. The average cost of 
filling silos of 100 tons or less capacity was found to be 70 cents; 
100 ton to 200 ton silos 58 cents, and silos ®ver 200 tons 57 cents. 
The average for all the silos in\-estigated was found to be 62 cents. 

Recent investigations by the University of Illinois show the aver- 
age cost of filling silos, including cutting crop in field, to be 58 cents 
per ton in Illinois, which figure compares favorably with the average 
of 57j^2 cents obtained in the investigation conducted by this com- 
pany. Farmers' Bulletin No. 292 on the "Cost of Filling Silos," 
shows a range of 46 cents to 86 cents per ton on the 31 silos inves- 
tigated, giving an average of 64 cents as against the average of 62 
cents obtained in the investigation conducted by this Company. 

Total Cost of Silage: — The same elements which determine the 
cost of filling the silo, determine the total cost of the silage, with 
additional items including cost of the land, cost of tillage and interest 
on investment. Farmers' Bulletin No. 32 states that "In the writer's 
experience in the Central West the cost on high-priced land has been 




Fiy;. 10. Silo \\ ith concrelo root iiiiil chutf 
on the farm of Dr. Hammond, Wheaton. 111. 
Built by the New Enterprise Concrete 
Machinery Company, Chicago. 



UNIVERSAL PORTLAND CEMENT CO. 



21 



.j^RpV^HHRa^ 




about $1.50 per ton. F. S. Peer in a recent book which treats of silos 
and silage, gives the cost in his experience as $1.20 per ton. Professor 
Wall of Wisconsin, places it at $1.00 
per ton to $1.50 per ton, including 
cost of seed, preparation of land, in- 
terest on investment, cultivation of 
the crop, cutting and filling- the silo. 
King, when studying this subject in 
Wisconsin, found that for a number 
of farms in that State, the cost 
averaged 7'^]/^ cents per ton." 

Farmers in the vicinity of Or- 
chard Ohio, have computed the cost 
of their silage at $1.12 per ton. Mr. 
James Dorsey, of Gilberts, Illinois, 
puts the full cost at $1.00 per ton 
in his section of the country. Some 
years ago silage cost $1.50 per ton 
at the Purdue Experiment Station 
and farmers in various parts of In- 
diana estimated the cost of their 

silage at 50 cents to $2.00 per ton. Fig. U. Concrete stave silo of Mr. H. R. 

•^ Hanson, near Clarkfield, Minnesota. Built 

T,- ,1 r- ,1 . r by the Minnesota Silo Company, Willmar, 

It these figures on the cost Ot Minnesota. 

silage are compared with those for 

hay or other dry feed, silage will be found much cheaper; to this ad- 
vantage must be added that of the larger milk flow obtained where 
silage is fed. 

Using off the Silage 

SILAGE is always used oiT the top of the silo. Any opening in 
the bottom would admit air, which would cause the silage to 
spoil. A large number of farmers commence to feed out of the 
silo as soon as filling is completed, thus avoiding any loss whatever 
on the top. If this is not done, the shallow covering of spoiled silage 
must be removed and thrown away when feeding is begun. The silage 
must be fed off in layers of at least two inches each day in order to 
prevent the formation of mold. 

Most authorities advise that the surface of the silage be kept as 
nearly level as possible so as to present the smallest possible surface 
to the air. In some parts of the country, however, where the winters 
are severe, it is common practice to keep the edges lower than the 
center, making the surface of the silage cone-shaped. This is said to 
prevent to a large extent the freezing which sometimes occurs around 
the edges near the top. 

Never throw down the chute more silage than will be required 
immediately, being careful to keep the doors between the chute and 
the barn closed whenever not in actual use. Care in this respect will 
keep silage odors from reaching the barn. 



22 



CONCRETE SILOS 




u 



The Advantage of Concrete as 
a Silo Material 

IT HAS been admitted by tbose who have studied the subject 
from an impartial standpoint, that silage can be kept m good 
condition in a silo of any material— be it concrete, stone, tde_, or 

wood— if the material selected is properly used. The length of time 

for which the silo will continue to fulfill in a satisfactory manner the 

service required of it depends, how- 
^^__ _, ever, upon the selection of the ma- 
terial best able to combat the action 
of the elements, withstand the 
heavy strains due to the silage, and 
furnish a reserve for such extraor- 
dinary conditions as fires and cy- 
clones. 

Concrete — whether placed in 
forms or cast in l)locks — is the ideal 
silo material l)ecause it is perma- 
nent, wind-proof, rodent-proof and 
hre-proof, and is economical in first 
cost and maintenance. As regards 
permanency, there is no cpiestion 
i'Ut that a good concrete silo will re- 
main indefinitely. Concrete grows 
-nduger and tougher witli age, out- 
lasting almost every other known 
material. Reinforced concrete is the 
strougest and most endin-ing con- 
struction known. It is selected for 

the great engineering projects — long bridges, massive dams, and lofty 

skyscrapers. 

While great financial loss seldom follows the collapse of a silo 
due to wind pres.-^uro, the matter is worthy of consideration because 
of the frequency with which wooden silos blow down. Indeed, 
in many parts of the country wooden silos can be found which have 
blown down three or four times. The development, during the past 
ten years, of slender reinforced concrete chimneys of great height, 
shows that from a standpoint of safety against wind resistance, this 
type of construction is unequaled. 

Mice have been known to cause considerable loss by burrowing 
into vv^ooden silos. IVIice holes allow the air to get in, often causing 
the silage to spoil for a foot or more in all directions from the holes. 
Mrs. L. H. Adams, of Parma, Michigan, had an experience of this 
sort, and as she has a concrete silo of the same size adjoining the stave 
silo, a fair comparison between the two is easily made. The loss of 
silage from mice holes in the wooden silo brought the total loss in 
that silo up to more than twice the loss in the concrete silo, notwith- 
standing the fact that the latter vvas not provided with roof, chute, 
or doors, the continuous door openings being roughly boarded up. 



tal Farm ot the South Dako 
Brookings, South Uikota. 



UNIVERSAL PORTLAND CEAIENT CO. 



23 



Concrete silos prevent silage from drying- out. The old 
idea that the juices of the corn seep through concrete walls with bad 
effect upon the latter has been entirely disproved — in fact, it ..ever has 
been entertained for a minute by owners of concrete silos. The 
bugaboo of a concrete silo disinte- 
grating through the action of corn 
acids is an absurdity. There are 
hundreds of cases where the con- 
crete bases and floors of wooden 
silos have been in use for a long 
term of years without discoloring 
or disintegrating in the least, show- 
ing conclusively that silage acids 
have no effect on good concrete. 

Fireproof Construction 




Fig. 13. 11x28 monolithic silo, built by Gar- 
rett Wierenga. Hudsonville, Mich. Capac- 
ity, 51 tons; cosi, complete, S105. This silo 
%vas put up in 1.5 days by Mr. Wierenga, with 
the assistance of farm hands. Since com- 
pletion, two years ago, the silo has given 
excellent satisfaction. 



The farmer, of all people, i 
the mercy of fire. Let a blaze ( 
start in or about his barns and 
chances are small for saving a 
the surrounding structures. Fire 
fighting apparatus is out of the 
f|nestion, the Avater supply is gen- 
erall}^ limited, and in nine cases out 
of ten help cannot be summoned 
until the flames are beyond cont 

Silo fires usually cause great loss 
because the feeder of silage is entirely 
dependent upon his silo all through 
the feeding season, which covers the 
greater part of and sometimes the 
entire year. The loss of the silo fre- 
quently means that the cattle have to 

be sold off, always at considerable sacrifice. Concrete silos of either 
the monolithic or block type are absolutely fireproof — of such a con- 
struction that they might be used for chimneys. If equipped with a 
concrete chute the concrete silo will protect the silage perfectly, and in 
the event of a fire not a pound need be lost. 

Mr. George Pulling's Silo: — During the winter of 1910 fire de- 
stroyed the barn of Mr. George Pulling, near Parma, Michigan, ad- 
jacent to which was Mr. Pulling's new 85-ton monolithic silo, erected 
at an expense of $300.00. This silo, one of a large number of similar 
ones put up in that part of the country by Mr. Charles Nobles, of 
Kalamazoo, came through the fire in good shape, with silage in per- 
fect condition. At the time of the fire the silo contained about 50 
tons of corn silage, and as hay was then selling in the vicinity for 
$15 per ton, dry feed to take the place of the silage w^ould have cost 
probably $500, an amount greater than the cost of the silo and silage 
combined. 



24 



CONCRETE SILOS 



Mr. A. B. Main's Silo: — A striking example of the value of fire- 
proof silo construction is presented in the accompanying illustrations, 
showing .he 550 ton concrete block silo of Mr. Arthur B. Main, Dela- 
ware, Ohio, before and after the disastrous fire which destroyed his 
barn in October, 1910. This silo was built for Mr. Main during the 






% 



'M 




Before the fire 



L 







Fig. 14. Concrete Bbck Silo of Arthur B. Main, Delaware, Ohio. This silo is 20 
feet in diameter and 60 feet in height and was built by the Perfect Cement Silo and 
Cistern Company, Delaware, Ohio. The adjoining barn with 180 tons of hay burned 
during the autumn of 1910. The silo shows no other effects of the fire than those 
which can be seen in tht illustration. Its 530 tons of silage were kept in perfect con- 
dition with a loss of less than 300 pounds. 



UNIVERSAL PORTLAND CEMENT CO. 



25 



summer of 1909 by the Perfect Cement Silo & Cistern Company of 
Delaware. 

At the time of the fire Mr. Main was feeding between 80 and 90 
head of cattle and had on hand 530 tons of corn silage and 180 tons 
of hay, the latter being stored in the end of the barn adjacent to the 
silo. The barn burned to the 
ground, leaving nothing but the 
concrete footings, which will be no- 
ticed in the lower illustration. 

Although the silo was sub- 
jected to intense heat, the only 
damage done was the burning out 
of the continuous wooden doors. 
Perhaps the most remarkable fact 
brought out in connection wnth the 
fire was that of the small amount of 
silage lost. After the destruction of 
the doors the surface of the silage 
presented to the flames was seared 
and charred to a slight extent. l)ut 
the charred or spoiled layer had a 
thickness of less than half an inch, 
and the amount actually lost was 
insignificant. 

Had Mr. Main been deprived of 
his silage by fire, it is safe to say 
that his dairy business would have 
been ruined, temporarily, at least. 
At the time of the fire hay was sell- 
ing at $15 per ton. Had it been 
possible for him to have substituted 
a daily ration of 40 pounds of hay 
per cow for the 40 pounds of silage 
and 10 pounds of hay being fed, the cost would have been no less 
than $4,000. Mr. Main could not, however, have purchased the dry 
ieed with which to have fed his herd through the season ; even had 
that been possible, the hauling of a sufficient quantity of dry feed 
a considerable distance over bad roads would have been impractical, 
according to his statement. The only course left open would have 
been to dispose of his cattle, which would have meant a large loss. 

The cost of Mr. Main's silage was estimated at $1.12 per ton, or 
a total of $593.60. The silo cost $750 complete. The total cost, 
therefore, of silo and silage as they stood at the time of the fire was 
about $1,343.60. Had the silage been destroyed, the cost of sub- 
stituting dry feed would have amounted to about three tiines the 
cost of the concrete silo and its contents. These figures are sufficient 
to convince the thoughtful farmer of the desirabilit}^ of putting up 
fireproof silos. 




Fig. 15. Silo of Mr. George A. Fox, Syca- 
more, 111. 16 feet in diameter; 40 feet in 
height. Built by the Polk -Genung- Polk 
Company. This illustration shows clearly 
the Polk elliptical door openings. 



26 



CONCRETE SILOS 




'l.fel**f2^ 



The Element of Waste 

All available data tend to show that the waste of silage in silos 
built of concrete is fully as small, if not smaller, than in silos of any 
other material. Of 50 silos in the states of Illinois, Michigan, Wis- 
consin, Indiana. Ohio, Kentucky and Missouri, on which reliable data 
was obtained, 25 showed a loss of less than one-half ton of silage 

from all causes, 18 showed a loss be- 
tween one-half ton and two tons, and 
7 showed a loss of more than two 
tons. In terms of percentage of the 
total silage in each silo, it was found 
that thirty-four had an annual loss of 
less than one per cent, thirteen had 
a loss between one and three per 
cent, three had a loss greater than 
three per cent. The greatest loss in 
any case was about six per cent. 

These figures arc somewhat 
lower than tlufse recorded at some 
(if the state agricultural colleges, 
probably for the reason that the col- 
lege dairymen are more particular 
than the average farmer, rejecting 
silage which the latter would con- 
sider fit for use. It may be stated 
conservatively that with silage crop 
in good condition when put in, 
properly tramped down and fed out 
at the rate of 2 inches or more per 
day, the loss in concrete silos of 
either the monolithic or block type will seldom, if ever, reach 5 per cent. 
There is practically no waste in cases where the cattle are placed 
upon a silage ration as soon as filling is completed. Where this is not 
done, the waste is minimized by wetting and tramping the silage down 
and planting oats or rye on top, as previously suggested. 

The Effects of Freezing 

The subject of frozen silage has attracted considerable attention, 
more perhaps than its just due. The fact has been pretty well 
established that freezing is an inconvenience rather than a real det- 
riment. Silage which has been frozen has to be handled an extra 
time, being either pitched to the center of the silo with the warmer 
silage, or removed to the barn to thaw. In either case, only enough 
of the frozen silage is thawed out each time to supply the next feed- 
ing. Silage keeps indefinitely while frozen, and instances are noted 
where it has not spoiled after thawing, when left packed in the silo. 

After thoroughly thawing out, silage which has been frozen 
is equally as nutritious as before freezing, and the cattle eat it with 
as great relish. Silage in the frozen condition is liable to produce 
harmful effects, and should never be fed. "All careful stockmen heat 
their drinking water," says Wisconsin Bulletin No. 125, "but it is a 



Fig. 16. Monolithic silo on the farm of 
John Judge. St. Charles, 111. Muilt hy C. \. 
Anderson, St. Charles. Cost, complete, 
$490, including concrete chute; capacity. 
175 tons of silage. Forty silos of this type 
have been put up by Mr. Anderson in Kane 
county, 111. 



UNIVERSAL PORTLAND CEMENT CO. 



27 



^^^; 



much more serious matter to feed a cow 40 pounds of silage at 32 
degrees than to give her 20 to 30 pounds of ice water." 

Freezing is caused by the loss of heat through the walls and 
from the contact of the feeding surface with the air. The former 
loss is made somewhat less when hollow block or monolithic walls 
with air spaces are used, but even in the case of single monolithic 
walls, loss of silage from freezing 
is extremely rare. In northern 
Minnesota and North Dakota, where 
the temperature frequently reaches 30 
degrees below zero during the winter, 
and occasionally goes as low as 40 
degrees below, both monolithic and 
concrete block silos ;ire in successful 
use. For parts of the country where 
such extremely cold weather is en- 
countered during the winter months, 
the hollow wall construction is to be 
preferred. However, a recent in- 
vestigation of concrete silos in Minn- 
esota failed to disclose any in which 
the silage froze more than one foot 
back from the wall on the north side. 
Freezing to this extent occurred when 
the temperature was between 30 de- 
grees and 40 degrees below zero. 

Prof. J. H. Shepperd, dean of 
the North Dakota Agricultural Col- 
lege, says in a recent letter: 

"I might say that our experience here indicates that there is no 
difficulty in putting up the ordinary type of silo in this state by reason 
of the cold weather which occurs during the winter season. Our 
farmers who have had experience with them recommend building 
them outside of the barn rather than to put them inside to protect 
them from heavy freezing of the ensilage on the walls. I think there 
will be a large increase in the number of silos in -this state in the next 
few years." 




Fig. 17. A concrete silo which failed. Miss 
Kate Virtue, owner. Hudson, Wis. The 
contractor in this case used poor materials, 
lean mixtures and inadequate reinforcing. 
The walls cracked during the first filling, 
and were reinforced with iron bands. They 
w^ere later repaired with grout. The silage 
has kept in perfect condition notwithstand- 
ing the faulty construction. 



Silo Failures 



ALTHOUGH failures of concrete silos arc extremely rare, the 
few cases which have arisen have been given wide 
publicity as proof that concrete is not a suitable material for 
this class of w-ork. Almost without exception, the failures which have 
occurred have been due to insufficient reinforcing, a cause which 
affects silos of other materials to as great an extent. One or two 
cases have been seen where poor materials have contributed to the 
failure, and in one instance cracks occurred between the courses of a 
monolithic silo due to poor bond at points where concreting was dis- 
continued. This condition might have been prevented by the treat- 



28 



CONCRETE SILOS 



flpr 




ment described on page 54. The use of dirty, poorly proportioned, 
weak aggregates, mixed without sufficient water or cement, will not 
give satisfaction, and the sooner discontinued, the better. There is 
no reason for a single failure, if sufficient reinforcing is properly 
put in, materials are clean and well proportioned, and the work 
done in accordance with the directions laid down in the following- pages. 

The silo shown in 

— - Figure 18 is especially 

I interesting, because 

it has been widely 
used by manufactu- 
rers of other types of 
silos, as a strong ex- 
ample of concrete silo 
failure. So far as can 
be learned, however, 
none of these parties 
have ever tried to 
ascertain the true 
reason for the failure, 
which might have 
1>een made perfectly 
clear by a short in- 
vestigation. Bulletin 
No. 100 by the Iowa 
State Agricultural 
College says : 

' 'There is an excess 
of juice in pea vines 
and in order to pre- 
vent an accumulation of this and a consequent excessive internal press- 
ure, a large drain was placed at the center of the silo. This drain for 
the first two years accomplished its purpose, but upon the third filling 
it became clogged, allowing the juices to accumulate to a depth of at least 
20 feet. By calculation it was determined that the bursting pressure in 
the silo due to the 20 feet of juice was more than double the strength of 
the steel reinforcement in the wall for the bottom 18 inches. This shows 
conclusively that the concrete was not at fault and this instance cannot 
be used as an argument against the concrete silo. If the silo is filled 
with corn, that is properly matured, the above conditions cannot occur. ' ' 
The above only partly explains the difficulty. An investigation 
shows that the walls w^ere reinforced by five-eighths-inch rods, spaced 
eighteen inches apart at the bottom, increasing to three feet at the 
top, which is not enough to properly reinforce a silo twenty feet in 
diameter. This silo has a diameter of sixty feet, a height of forty 
feet, and a capacity of 2.250 tons, about eight times as great as that 
of a silo of the same height, twenty feet in diameter. 

Concrete Silos in the South 

A large number of monolithic, concrete block and cement plaster 
silos have been put up throughout the South, many excellent examples 



FiK- I^. 1-artro moiiolithu (.oncTfte silo, hiiili for 
Canning Company, Waukesha, ^^■isconsin. One 
silos in the world. Capacity. 2,2.iO tons ; cost, S2„S( 
pea vines, producing: silage as a bi-product of the 



[hi- W'aiikcslia 
of the largest 
1). Filled with 
L-annery. 



UNIVERSAL PORTLAND CEMENT CO. 



29 



being- reported in the states of Maryland, Virginia, North and South 
Carolina, Georgia, Alabama and Mississippi. Without exception these 
silos are giving splendid satisfaction, and it is only because of the lack of 
time in preparing the present book- 
let that the methods of constructing 
silos in the southern states are not 
fully discussed. 

Cement plaster silos built by ap- 
plying a coat of stucco to a metal 
frame is a type peculiar to this sec- 
lion and has been recommended by 
one or two of the Sonthern Agricul- 
tural Schools. 

The following extract from a let- 
ter from Prof. J. A. Conover, of the 
U. S. Naval Academy at Annapolis, 
gives his experience in constructing 
concrete silos in North Carolina : 

"In connection with my work 
with the North Carolina Depart- 
ment of Agriculture, I have built 
during the past five years a large 
number of concrete and cement 
plaster silos and they are all giving 
excellent satisfaction. Where the 
silage was properly packed it has kept 
splendidly. These silos were all 
given a coat of coal tar inside before 
filling, which I believe is a necessity. 




Fig. 19. Concrete block silo, built for Rev. 
Joy Halliday, Delaware, Ohio, by the Perfect 
cement Silo and Cistern Co., of Delaware, 
O., Dimensions, 15 feet in diameter by 50 
feet in height. As in the case of other silos 
in this vicinity, no roof is used. 



inches thick, the plaster being 



The concrete silos had 6-inch 
walls reinforced with woven 
wire fencing all the way up. We 
used a standard fence from 30 to 
48 inches in height. The plastered 
silos had walls only about 2h 
put on expanded metal lath bent and wired in a circle. No 
other reinforcing- was used. One of these silos has been up five years 
and as far as I can see it is just as good as it was when first completed. 
"These silos were all put up by farm labor and did not cost 
nearly as much as they would had they been built by such labor as 
one gets in the city. One silo 12x24 only cost its owner $80.00. One 
of the expanded metal lath plastered silos 14x28 cost $181.00 including 
roof, painting (tarring) and everything complete. AVood has reached 
such a figure and lasts such a short time that I believe it is much 
cheaper to build of concrete. I am not familiar with concrete sdos 
in the North, but for the South I do not think there can be anything 
better. I expect to build two concrete silos 16x32 for the Naval 
Academy Dairy this summer." 



30 



CONCRETE SILOS 



What It Costs to Build a Concrete Silo 



TABLES E and F show the dimensions, tonnage, and actual 
cost of 7^ monolithic and 30 block silos, compiled from data 
collected during the Spring of 191L Total costs given include 
material, labor, superintendence and all miscellaneous expenses in- 
curred in putting the silos in place to receive the crops. Exchange 
labor lias been figured in at the prevailing rates for day labor in the 

same communities. Where sand 

and gravel have been obtained on 

_ the place, the expense of hauling 

<*'^" - plus a fair price for the materials 

has been included in the total cost. 

The following figures given in 

I terms of cost per ton of capacity 

\ represent averages taken from the 

tal)les: 

Average Cost of Silos. 

Per Ton of Capacity. 

Monolithic. Block. 

Illinois $2.83 $2.44* 

Michigan 2.31 3.21 

Wisconsin 2.10 3.36 

Minnesota 2.26 3.34 

Average cost of all 
silos, capacitv 100 

"^ tons or less..' 2.89 3.52 

"*1 Average cost of all 
i silos, capacitv 100 

..^ to 200 tons .' 2.38 2.88 

Fig. 20, Monolithic silo on tlio farm of Mr. Ayp^oo-p cost of all 

S.S.Lee, Lowell, Mich., built during 1910 by -^\C'dj,C CUbU ui du 
R. C. Angevine, Coldwater. Diameter, 14 SlIOS, Capacity 

feet; height, 36 feet Cost, $350. complete ^^ore than 200 tonS 2.18 

except for gravel and scaffold. 

Average cost of all 
silos 2.30 3.11 

The cost of a concrete silo depends primarily upon local condi- 
tions. The price of gravel and cement and the cost of labor are the 
determining factors. These vary so greatly, however, with time and 
place that no attempt will be made to give them here. A good con- 
crete silo of either monolithic or block construction usually costs no 
more, and in some cases a great deal less, than a good wood, brick or 
tile silo. The concrete silo has the advantage of a lower cost of 
up-keep. 




*Taken from only two silos. A fair average for the State would 
undoubtedly be much higher. 



UNIVERSAL PORTLAND CEMENT CO. 



31 



TABLE E. 







COST OF MONOLITHIC SILOS. 


Silo 
No. 


Diameter 

in ft. 


Height 
^n ft. 


Capacity 
in tons 


Entire 
Cost 


Cost per 

ton of 
capacity 


Location 


1 


16 


37 


161 


$ 525 


? 3.26 


Belvidere, Illinois 


2 


16 


44 


207 


695 


3.36 


Carlton, 


3 


15 


30 


105 


400 


3.81 


Downer's Grove, " 


4 


16 


2)2 


131 


500 


3.82 


Downer's Grove, " 


5 


20 


40 


282 


550 


1.95 


Dundee, " 


6 


20 


40 


282 


720 


2.56 


Dundee, " 


7 


12 


27 


58 


241 


4.15 


Effingham, " 


8 


18 


40 


228 


620 


2.62 


Elburn, " 


9 


18 


40 


228 


620 


2.62 


Elburn, " 


10 


20 


40 


282 


680 


2.41 


Elburn, " 


11 


20 


40 


282 


680 


2.41 


Elburn, " 


14 


16 


40 


180 


550 


3.05 


Kaneville, " 


15 


17 


42 


218 


650 


2.98 


Lake Forest, 


16 


17 


42 


218 


650 


2.08 


Lake Forest, " 


17 


18 


46 


277 


650 


2.35 


Marengo, 


18 


18 


36 ^S 


200 


409 


2.09 


Pingree Grove, " 


20 


18 


34 


181 


490 


2.70 


St. Charles, 


21 


16 


30 


119 


405 


3.40 


St. Charles, 


22 


20 


40 


282 


680 


2.41 


St. Charles, 


23 


18 


38 


212 


575 


2.72 


St. Charles, 


24 


12 


38 


94 


300 


3.19 


St. Jacob, 


25 


18 


40 


228 


550 


2.41 


Wheaton, 


26 


24 


50 


550 








27 


24 


50 


550 


1600 


.97 


Winslow, " 


28 


24 


50 


550 








29 


20 


40 


282 


500 


i.'76 


Coldwater, Micliigan, 


30 


20 


40 


282 


500 


1.76 


Coldwater, 


32 


14 


45 


165 


306 


1.87 


Eau Claire, 


33 


14 


46 


170 


400 


2.35 


Eau Claire, 


34 


12K. 


36 


95 


163 


1.72 


Eau Claire, 


35 


14 


36 


lis 


200 


1.70 


Eau Claire, 


36 






55 


190 


3.45 


Grandville, " 


37 


ii 


28 


51 


105 


2.06 


Hudsonville, " 


38 


14 


28 


83 


250 


3.00 


Kalamazoo, " 


39 


12 


30 


67 


250 


Zj2 


Kalamazoo, " 


42 


14 


30 


91 


130 


1.43 


Lansing, " 


43 


14 


Z2 


100 


169 


1.69 


Lansing, 


44 


18 


40 


228 


550 


2.41 


Marquette, " 


45 


14 


40 


138 


295 


2.14 


Parma, " 


46 


14 


40 


138 


300 


2.18 


Parma, 


47 


12 


36 


87 


230 


2.64 


Parma, " 


48 


12 


36 


87 


240 


2.75 


Parma, 


49 


12 


36 


87 


300 


3.45 


Parma, 


50 


14 


47 


175 


300 


1.72 


Sodus, 


57 


20 


45 


330 


550 


1.67 


Cedarburg, Wisconsin, 


58 


20 


45 


330 


550 


1.67 


Cedarburg, 


61 


16 


30 


120 


500 


4.16 


Elkhorn, 


64 


16 


40 


180 


275 


1.53 


Hudson, 


65 


14 


52 


190 


600 


3.16 


Irma, " 


66 


14 


36 


118 


175 


1.48 


Lake Geneva, 


68 


14 


36 


118 


293 


2.48 


Madison, " 


71 


16 


30 


120 


260 


2.16 


New Richmond, " 


n 


16 


30 


120 


260 


2.16 


New Richmond, " 


73 


16 


37 


161 


199 


1.24 


New Richmond, " 


74 


13 


30 


79 


168 


2.13 


Roberts, 


75 


16 


30 


120 


114 


.95 


Roberts, 


76 


16 


30 


120 


180 


1.50 


Roberts, 



32 



CONCRETE SILOS 



TABLE E— Continued. 



Silo 


Diam- 


Height 


Capacity 


Entire 
cost 


Cost per 
ton of 


LOCATION 


No. 


in feet 


feet 


tons 


capacity 




77 


16 


30 


120 


177 


1.47 


Roberts, Wisconsin 


78 


16 


38 


167 


195 


1.17 


Roberts, 


79 


14 


35 


114 


325 


2.85 


Walworth, 


80 


14 


28 


83 


400 


4.80 


Walworth, 


81 


60 


40 


2250 


2500 


1.11 


Waukesha, " 


85 


14 


29 


87 


115 


1.32 


Jordan, Minnesota 


89 


20 


32 


205 


380 


1.85 


Owattona, " 


90 


14 


28 


83 


214 


2.58 


Rose Creek, 


93 


16 K^ 


33 


144 


475 


3.30 


Wheaton, 


94 


20 


40 


282 


500 


1.77 


Centerville, Indiana 


95 


16 


38 


167 


500 


2.99 


Fort Wayne, 


96 


16 


40 


180 


550 


3.05 


Huntington, 


97 


14 


30 


91 


340 


3.74 


Oil City, 


102 


16 


40 


180 


344 


1.91 


Roanoke, Missouri 


103 


16 


32 


131 


315 


2.40 


Springfield, 


104 


12 


30 


67 


250 


Z.72 


High Bridge, Kentucky 


105 


18 


38 


211 


204 


.97 


West Paint Lick. " 


106 


12 


24 


49 


145 


2.96 


Fort Collins, Colorado 


107 


12 


24 


49 


165 


3.36 


Fort Collins, " 


108 


17 


38 


190 


400 


2.10 


Iowa City, Iowa 


110 


18 


40 


228 


600 


2.64 


Warren. Pennsylvania 



TABLE F. 
COST OF CONCRETE BLOCK SILOS. 



Silo 

No. 


Diam- 
eter 
in feet 


Height 

in 

feet 


Capacity 

in 

ton.s 


Entire 
cost 


Cost per 

ton of 
capacity 


LOCATION 


12 


16 


38 


167 


$ 450 


$ 2.70 


Kaneville, Illinois 


13 


16 


44 


207 


450 


2.18 


Kaneville, 


31 


12 


32 


74 


163 


2.20 


Coloma, Michigan 


40 


12 


30 


67 


138 


2.06 


Lansing, " 


41 


12 


38 


94 


180 


1.92 


Lansing, 


51 


8 


37 


40 


227 


5.70 


Sodus, 


52 


12 


30 


67 


300 


4.48 


Sodus, " 


53 


12 


30 


67 


180 


2.70 


Zeeland, 


54 


10 


20 


36 


110 


4.20 


Zeeland, 


55 


10 


28 


42 


160 


3.80 


Zeeland, " 


56 


10 K^ 


28 


45 


170 


3.78 


Zeeland, 


59 


16 


34 


143 


340 


2.38 


East Troy, Wisconsin 


60 


14 


35 


114 


300 


2.64 


East Troy, 


62 


14 


30 


91 


450 


4.95 


Elkhorn, || 


63 


18 


33 


174 


400 


2.30 


Elkhorn, 


67 


12/. 


38 


100 


500 


5.00 


Lake Geneva, 


69 


16 


32 


131 


410 


3.13 


New Richmond, " 


70 


16 


32 


131 


410 


3.13 


New Richmond, "' 


82 


16 


42 


193 


550 


2.83 


Austin, Minnesota 


83 


16 


30 


119 


400 


3.36 


Claremont " 


84 


16 


32 


131 


400 


3.05 


Claremont, 


86 


14 


32 


100 


312 


3.12 


Litchfield. 


87 


14 


32 


100 


380 


3.80 


Northfield, " 


88 


14 


32 


100 


375 


3.75 


Northfield, 


92 


14 


32 


100 


225 


2.25 


Stillwater Jet, 


98 


20 


60 


530 


750 


1.42 


Delaware, Ohio 


99 


14 


40 


138 


420 


3.04 


Greenfield, 


100 


12 


33 K. 


80 


250 


3.12 


Lorain, 


101 


12 


30 


67 


200 


2.98 


Marysville, " 


109 


16 


34/2 


146 


475 


3.25 


Butler, Pennsylvania 



UNIVERSAL PORTLAND CEMENT CO. 



33 



Time Required to Build Concrete Silos 

THE average time required to construct a monolithic silo is from 
one to two weeks, depending upon the height, number of men 
on the job, conditions of weather, and the height of wall 
accommodated by the forms at a single iilling. Where the work is 
done by home labor and there is no contractor or competent foreman 
in charge, occasionally more than 2 
weeks are required to complete the 
work. The block silo can usually 
be put up in 4 days to a week, de- 
pending upon its size and the num- 
ber of block masons employed. 
After completion it should be al- 
lowed to stand at least a week be- 
fore filling, to allow the mortar to 
become firm and hard. If the silo is 
to be filled during the early part of 
September, work on the foundation 
should be commenced no later than 
August 20th. In all cases the silo 
should be completed several days 
before being subjected to the strain 
caused l)v filling. 

A Comparison of the Monolithic and 
Concrete Block Types. 

Two general methods of con- 
crete construction are available for 
silo work — the monolithic and the 
concrete block. With the former 
method, the materials are hauled to 
the site of the silo and there mixed 
and placed within forms; the latter method reciuires that the block be 
made and cured in some convenient place, and later hauled to the site 
to be laid up in the wall. 

Each method has certain advantages and disadvantages, but the 
matter of personal choice generally influences the decision to build 
either with monolithic walls or with block. The monolithic silo is 
generally the easier of the two for inexperienced persons to build, and 
is usually a little cheaper than the block, as it does not require the 
service of good masons or the use of a block machine; the block silo, 
however, makes the use of forms unnecessary, produces a wall with 
continuous vertical air spaces, and slightly reduces the amount of 
materials used. 

The decision to build either of monolithic or of block construc- 
tion very often depends upon the availability of materials. In locali- 
ties where materials for monolithic work are abundant and of good 
quality, it is hardly practical to haul blocks farther than eight or ten 
miles; on the other hand, if there is no good sand or gravel nearby, 
block work may be preferred to the monolithic. In such cases, it may 
be found economical to haul blocks from a greater distance, or make 
them on the site, if need be. 




Fig. 21. Block silo of C. E. Deaner, Sodus. 
Mich. Although Mr. Deaner has but 17 acres 
of land, he has a 40-ton silo (diameter, 8 feet; 
height, 37 feet) . Mr. Carl Tillstrom, Benton 
Harbor, Mich., was the contractor. This 
silo was erected complete in 8 days. 



34 



CONCRETE SILOS 



Building the Silo 



CONTRACT WORK:— Where the services of reliable concrete 
silo contractors can be obtained, it is generally advantageous 
to have the silo built under contract. The cost of silos built in 
this manner is generally no more than otherwise when quality of the 
work, convenience and time are considered. The advantages of good 

system, competent overseeing and 
general experience in the work justi- 
fies a greater cash outlay than is 
needed for home-made silos, al- 
though in a great many cases the 
actual expense of a silo built under 
contract is no greater than if built 
by the owner. If it is desired to put 
up the silo during a time of year 
when work is over plentiful or farm 
labor scarce, building the silo under 
, '■..^lil ^^ ^B contract will solve the labor prob 

I 




Fig. 22. One of the numerous concrete silos 
around Coldwater, Mich. E. W. Treat, 
owner. Diameter, 14 feet; heigfht, 40 feet; 
capacity, 140 tons. 



Of 110 concrete silos recently 
inspected, 74 Avere built by con- 
tractors, 9 by the owners under ex- 
perienced foremen, and 27 by the 
owners without any assistance 
\\hatever. In over one-half of the 
cases where the silo was built under 
contract the owner furnished a part 
(if the labor, and in about one-fifth 
nf the cases the owners furnished 
tlie cement. Almost without ex- 
ception, the owners of contract-built 
silos furnished the sand and gravel, 
for which they received credit on 
their accounts, at a stipulated rate. 



Work Under Hired Foremen: — In a large number of instances 
farmers have built their own silos under the supervision of a com- 
petent foreman hired by the day. Foremen who make a business of 
superintending silo work frequently have their own forms which they 
rent to the farmer for a nominal sum. When the silo is built under 
contract, the farmer usually does the hauling, and sometimes fur- 
nishes the materials and a part of the labor ; when a foreman is 
employed, the farmer must buy and haul the materials, furnish the 
labor, and pay for the work as it progresses, without an accurate 
previous knowledge of the cost. In addition he sometimes has to 
build his own forms. 



UNIVERSAL PORTLAND CEMENT CO. 



35 



Work Under Home Supervision: — If neither a good contractor 
nor a good foreman is available, the farmer may undertake the build- 
ing of the silo, but he must pay close attention to the details of the 
work. The inexperienced worker with concrete too often considers 
cement a sort of magic material which may be used without precau- 
tion and still secure first class work. On the contrary, precautionary 
measures are constantly necessary and the directions given on the 
following pages must be carefully 
complied w^ith if the best results are 
to be obtained. To acquaint inexpe- 
rienced contractors as well as those 
desiring to build their own silos 
with the best practice, is the purpose 
of the two sections immediately fol- 
lowing. A later section is devoted 
to a description of several of the 
leading commercial silo forms now 
upon the market. 

Co-Operation in Silo Work: — 
Where there are several silos to be 
built in the immediate vicinit}^, and 
it is desired to use home-made 
forms and do the work with home 
labor, a very considerable saving 
can be made by co-operation. With 
moderately fair weather, such as 
usually prevails from April to Octo- 
ber, four or five farmers working to- 
gether can construct moderate size 
silos in an average time of less than 
two weeks, working but 4 hours per 
day, with one set of forms. In about 

two months' time they can complete a good silo on the place of each, 
without having this work interfere seriously with general farm duties, 
and at a comparatively small expense, as only one set of forms is used. 

In "The Farmer" for April 29. 1911, Mr. Charles Nelson, of 
Meeker County, Minnesota, concluded a letter on "Co-operation in 
Silo Building" with the following paragraph : "Farmers, get to- 
gether, buy in carload lots material for silos of whatever material 
desired. Co-operate in building, filling, and in the purchase of 
machinery. It means a saving of dollars and cents which may be 
needed for the home or for other improvements." 




Fig. 23. Monolithic concrete silo on farm of 
F. .1. Miirpliy, near Whoaton, Minn., built 
under the direction of Martin Peterson, con- 
tractor. Height, ii feet ; capacity, 144 tons. 



36 conc:rete silos 

Foundations 

Laying Out the Work: — The site of the silo having been selected 
and its size determined, the excavation should be laid out. This 
may be done conveniently with a sweep similar to the one shown in 
Figure 24. A heavy stake is driven in the center of the spot selected 
for the silo and allowed to project above the surface about one foot. 
The arm of the sweep may be made of a two-by-four at least two 
feet longer than one-half the inside diameter of the silo. The arm 
swings about the stake as a center, being held to the latter by a 
large spike. A chisel-shaped board or template is placed as shown 
on the arm of the sweep, so that when the latter is swung around the 
stake, the chisel-sb.aped l)oard will describe a circle with a diameter 
lYz feet greater than the inside diameter of the completed silo. 
This will give the outer line ol the excavation and also foundation. 




Figure 24. Simple sweep, convenient in laying out excavation. 

Excavating: — The cxcavatinn sliotild be carried to a depth not to 
exceed (> feet behiw tlic lldur of llic barn where tlie silage is to be fed. 
The objection to going deeper is tliat il adds to the labor in remov- 
ing the silage. In all cases. ho\\e\er, the foundation should be estab- 
lished below frost. All of the earth within the line described by the 
sweep should be removed down to a point one foot from the bottom, 
and below this the excavation should be made the shape and size of 
the foundation, 2 feet wide by 1 foot in depth, so ])laced that the outer 
edge will come directly up to the ctiV^o: of the excavation, assuming 
that the sides of the latter are perpendicular. 

If the silo is to be equipjied with a concrete chute, the founda- 
tion for the chute should be put in at the same time as that for the 
silo. As the chute is rectangular in sha])e, no difficultv should be 
encountered in excavating for the foundation, which will be at the 
same depth as the silo foundation, and two feet in width by one foot 
in depth. 

O Placing the Concrete : — The concrete for the foundations should 
be made in the proportion of 1 sack Portland cement to 3 cubic feet 
of coarse sand, ti) .S cubic feet of screened gravel or crushed stone. The 
sand should be free from clay or organic matter, and the gravel or 
stone should contain no particle smaller in size than 34 inch. The ma- 
terials must be thoroughly mixed and enough water added to give a 
quaky consistency. The concrete may usually be placed in the exca- 



UNIVERSAL PORTLAND CEMENT CO. 



37 



vation without any forms whatever, but in some kinds of soil light 
boards, held in position by stakes, may be necessary. The top of 
the foundation must be levelled off with a straight edged board 
and spirit level. After 24 hours, the foundations have generally 
hardened sufficiently so that the walls may be built upon them. 
Where soft ground or quicksand is encountered, the foundation may 
be made 3 or 4 feet in width, to provide plenty of footing. 




Figure 2.'>. Concrete Silo Footing and floor, siiitahle for either 
Monolithic or lilock Silos. 



Imbedding Reinforcing Rods: — If a monolithic silo is to be built, 
the vertical reinforcing for the walls, consisting of J^-inch round 
rods spaced 3 feet a])art, sliould be iinl)e(ldc(l in the foundation a 
distance of 8 or 9 inches. If a l)kick sikj is to be built no vertical 
reinforcing need be placed. 



TABLK G 
MATERIALS FOR SILO FOOTINGS AND FLOORS. 





-0 3 


Footings' 




Floor 


Footings and Floor 


Ilg 


Quantities 


Quantities 


Total Quantities 






Cement 


Sand 


Gravel 


Cement 


Sand 1 Gravel 




'^OU 


Bbls. 


vds. 1 yds. 


-^^uo 


Hbls. 


yds. 


yds. 


Bbls. 


vds. 1 yds. 


8 


LS 


1.8 


0.7 


1.4 


0,.S 


.62 


.25 


.46 


2.42 


0.93 


1.86 


10 


1.8 


2.2 


0.8 


1.6 


0.8 


1.00 


.37 


.75 


3.19 


1.17 


2.34 


12 


2.2 


2.7 


1.0 


2.0 


1.0 


1.25 


.46 


.92 


3.94 


1.46 


2.92 


14 


2.5 


3.1 


1.2 


2.4 


1.6 


2.00 


.75 


1.50 


5.08 


1.94 


3.77 


16 


2.9 


3.6 


1,3 


2,6 


2.2 


2.75 


1.00 


2.03 


6.33 


2.31 


4.62 


18 


3.2 


4.0 


1..S 


3.0 


2.8 


3.50 


1.30 


2.58 


7.47 


2.79 


5.58 


20 


.3.6 


4.4 


1.6 


3.2 


XS 


435 


1.60 


3.22 


8.74 


3.21 


6.42 


22 


3.9 


4.8 


1.8 


3.6 


4.3 


5.33 


2.00 


4.00 


10.13 


3.78 


7.56 



38 



CONCRETE SILOS 



The Floor: — After the foundation is completed, the earth within 
should be dug out for a depth of about 8 inches, and a concrete floor 
built as shown in Figure 25. The floor should be given a slight pitch 
in all directions "toward the center, and, if necessary, an outlet to a 
line of drain tile should be put in. Outlets are not usually provided in 
silo floors, but in one or two instances silos have failed because of the 
pressure of a large quantity of water accumulated under unusual 
conditions, with no provision for escape. In such cases the stress 
on the walls may reach two or three times that usually imposed by 
the silage. Although the majority of silos are not provided with a 
drain, it is undoubtedly a desirable feature. The top of the drain 
should be protected from accumulations on the silo floor, by a small 
wire mat. A 4-inch or 6-inch drain tile will be sufficient. The floor 
should be made of 1 -2)^2 :5 concrete. A smooth finish is not consid- 
ered necessary. 



if( 



'*^. 




^ 



Figure 26. Model of the Farmers Institute Silo Forms, which has been the 
means of showing scores of Northern Wisconsin farmers how to build con- 
crete silos. Forms built after this model cost $60 to $75. Mr. David Imrie, of 
Roberts, Wisconsin, is owner of this model. 



UNIVERSAL PORTLAND CEMENT CO. 



39 



Monolithic Concrete Silos 

THE word "Monolithic" coming from "mono" meaning one, and 
"lith" meaning stone, is used in concrete work to denote the 
objects of concrete which are one continuous solid mass or "as 
one stone." Contrasting with the monolithic are several systems of 
concrete construction such as the concrete block, concrete brick, con- 
crete tile, unit column and slab, and 
cement plaster. The systems of 
concrete construction most com- 
monly used are the monolithic and 
the concrete block. The object of 
the present section is to supply the 
necessary information for construct- 
ing monolithic silos, in cases where 
the work is all done by the owner 
who is dependent entirely upon his 
own resources, or by contractors not 
familiar with this class of work. 

Home-Made Forms. 

The form described and shown 
on the following pages is a combina- 
tion of the Wisconsin form, de- 
signed by the Agricultural Depart- 
ment of the University at Madison. 
under Professor C. A. Ocock, and 
the Farmers' Institute form, de- 
signed by Messrs. John and David 
Imrie of Roberts, Wisconsin. Both 
of these forms have been used with 
great success among the farmers of 
Wisconsin and adjoining states and 
appear to be in many respects the 
most practical forms yet devised. Figure 26 shows a photograph of a 
model of the Farmers' Institute Form. The model was obtained 
through the courtesy of Mr. David Imrie, who has introduced this 
form to hundreds of farmers in conjunction with the work of the 
Wisconsin Farmers' Institute. 

Description of Forms: — The inner form consists siniply of 16 
segments or ribs made of 2"xl2" plank, 16 cleats made of 2"x6" plank, 
a number of r'x6" matched floor boards, a quantity of No. 28 gauge 
galvanized sheet steel, and 64 ^-inch bolts 4^^ inches long. (See 
Figures 28 and 29.) 

In making the form it will be convenient to refer to the table 
of materials given on page 43, for the dimensions of the ribs. The 
procedure should be about as follows: 

Draw a circle on the barn floor, of a diameter two inches less 
than the inside diameter of the silo. For this purpose use a sweep 



Fig. 27. The first monolithic siio in Northern 
Wisconsin. buiU by G. W. Graham, of Rob- 
erts, with the Farmers Institute Silo Farms, a 
photo of which is shown on page 38. Mr. 
Graham's silo cost $114, and has a capacity 
of 120 tons. 



40 



CONCRETE SILOS 



with a soft pencil or crayon attached to one end. Do not use a cord 
and chalk as the former will stretch enough to distort the circle, and 
the latter will make too wide a line. Space off the circumference into 
eight equal distances. (These may be obtained by takiiig distance 
"C" from the table of materials.) For the ribs lay down the 2"xl2" 
planks on the circle drawn, marking the arc on each plank with the 
sweep. The length of the rib should also be marked off on the plank 
in a radial direction, using the sweep as a guide. All of the dimen- 
sions for the ribs may be obtained from the table of materials, if 
desired. A hole 4"x45^" is cut in the center of each rib, as shown in 
the sketch accompanying: the table of materials, page 43. 




J'o/r?t in Out^/de rorm 





f 


^^ ^ -^ 1 






, , 


t 


» - • • -1 



/f/ey at/on 
Figure 28. Plan of home made waa forms, and details of outside form. 



UNIVERSAL PORTLAND CEMENT CO. 



41 



The l"x6" flooring boards are sawed up into 3-foot lengths and 
nailed to the outer edges of the ribs, the latter being placed 2 feet 
apart center to center. These boards are covered with the galvan- 
ized sheet metal. Eight similar sections are made and are held togeth- 
er with 2"x6" cleats 2 feet long, cut to the same circle as the ribs. This 
is very important, as the sections are thus held to a true circle. The 



E'k 4 " wedge 



^ / 4'/z l>o/tj 



Faced with 
galvanized iron 




Figure 29. Perspective of Inner Wall Form, showing position of 2 in. x 4 in. 
Uprights upon which the Form is raised. 




Figure 30. Sectional Plan and Elevation of Continuous Doorway Used on 

Wisconsin Silos, also Sketches of Continuous Door and Device for 

raising outer Forms. 



42 



CONCRETE SILOS 



cleats are bolted on, and the form then tightened by means of two 
keys directly opposite, as shown in the plan and perspective Figures 
28 and 29. The keys are made of 2x4's 3 feet long, having a very 
slight taper. After the form is bolted together, the keys should be 
driven down. 

This form is provided with a very simple arrangement for sup- 
porting, also for raising and lowering. Each rib has a hole 4 inches 
by 41/2 inches centrally located, through which passes a 4x4 upright 
made of two 2x4's nailed together. One-half inch holes are drilled 
in these at intervals of two and one-half feet, corresponding holes 
on all of the uprights being at the same level. After raising the form 
to a new position, bolts are inserted in the holes directly under the 
bottom ribs of the form. As the work progresses upward additional 
2x4's are spliced on alternately. 

The outside form is made of heavy (No. 18 or No. 20 gauge) 
galvanized sheet steel 3 feet in width. The form is made in pieces 
connected with one-half inch bolts 12 inches long and threaded to 
permit loosening and tightening of the form when raised. Three 
strips of heavy band iron are riveted on each side of the joint, the 
ends near the joints being turned out at right angles and provided 
with holes to receive the bolts. These strips are clearly shown, in a 
somewhat exaggerated form, in the photograph of the model. A 
heavy wire handle is put on the outside form opposite each pair of 
2x4" uprights for the purpose of raising. To each handle is fastened 




Figure 31. Illustration showing the method of bracing the 
upright supports on which the inner forms rest. Bracing 
between adjacent uprights is put in every five feet; those 
joining opposite uprights are put on every fifteen feet. 



a ^-inch rope 6 feet long. This rope is run over a little bracket 
which slides up and down the uprights. 



UNIVERSAL PORTLAND CEMENT CO. 



43 



TABLE H 
MATERIALS FOR HOME MADE SILO FORMS 
For Silos with Inside Diameters 8 feet to 22 feet. 
16 — 2"xl2" plank, cut as per sizes given in table. 

r'x 6" boards, for quantity see table. 
16 — 2"x 6" cleats — 3' long, cut on radius "r." 

2"x 4" studding planed. (Required quantity equal to 16 times the height 
of the silo.) 

No. 22 Gauge galvanized sheet iron 3 feet wide. (For quantity see table.) 
No. 18 " " " " 3 " " ( " " " " ) 

64 H-inch bolts 4]/^ inches long (for cleats). 
8 Vi- " " 6 " " (under forms). 

6 Yz- " " 12 " " (for outer forms). 

4 Iron Straps H"x2"x3'0" 
12 " " i4"x2"x2'6" 




Fig. 32 — Inner Form Ribs 



Inside 
•Diam. 


Dimensions of 
inner form ribs 


3.ofl"x6" 

oards 3^ 
long in 
ler form 


No. 18 gauge 
galvanized 
sheet iron l' 


No 28 gauge 
galvanized 


of 










sheet iron Z' 


Silo 




B 


c 


R 


wide 


wide 












ZM .E 


Feet Needed 


Feet Needed 


8 ft. 


9 " 


2' Wa" 


3' 07/^" 


3' 11" 


51 


30' 3" 


25' 0" 


10 " 


8 " 


V 3 " 


3' lOj/^" 


4' 11" 


63 


36' 7" 


31' 6" 


12 " 


6M" 


4' 1^" 


4' 7^" 


5' 11" 


76 


42' 10" 


37' 8" 


14 " 


6 " 


4' 10^" 


5' So/s" 


6' 11" 


88 


49' 3" 


44' 0" 


16 " 


5 " 


5' 9 " 


6' 2/." 


7' 11" 


101 


55' 6" 


50' 0" 


18 " 


4//' 


6' 6H" 


7' Ok;" 


8' 11" 


113 


61' 9" 


56' 6" 


20 " 


3 " 


r AY^" 


T 934" 


9' 11" 


126 


68' 0" 


62' 10" 


22 " 


2i.<" 


8' 3 " 


8' 7^" 


10' 11" 


138 


74' 5" 


69' 2" 



Cost of Forms : — Forms of this type can be made for twenty-five 
to fifty dollars, and in one instance a farmer built an equipment similar 
to that described here at a cash outlay of only $15.00. Forms can 
generally be disposed of after use at a price equal to the total cash 
outlay to the builder, so that the use of these in building his silo 
only costs h^m his labor. A single set of forms is often used on sev- 
eral silos, each user selling his forms to the next man for a sum 
slightly less than what he paid for them. 

Care in Bracing Supports: — As the inner form is moved upwards it 
will be necessary to securely brace the uprigiit supports. This i.s very es- 
sential. No weak or rotten lumber should be used, and all bracing- 
should be put where it will carry the load in the best and most secure 
manner. The double two-by-four supi-)orts recommended have ample 
strength to carry the weight if properly braced, but this precaution must 
not be neglected. 

The uprights should be braced at intervals of five feet (every 
two courses) with horizontal boards running from one upright to the 
next, and braced back against the wall as shown in Figure 31. Boards 
l"x6" or 2"x4" will be large enough for this purpose. About every 15 



44 



CONCRETE SILOS 






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UNIVERSAL PORTLAND CEMENT CO. 45 



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46 



CONCRETE SILOS 



feet braces should be run across to opposite uprights, 2x4" or 2x6" 
material being used. 

Importance of a Smooth Wall: — In handling the inner forms, 
great care must be observed in keeping the inside surface of the silc 
perfectly smooth. Horizontal, "steps" in the wall are particularly 
objectionable. Projections, "steps" and other irregularities cause 
uneven settling of the silage, thus forming air pockets. The presence 
of an air pocket frequently causes silage within a foot of the pocket 
on all sides to spoil. 

Painting the Forms: — The inner surfaces of the forms should be 
painted before using, with crude oil or whitewash, which will prevent 




n rod's 
4"' 5 ^4^ channe/ 



Figure 33. Continuous Steel Doorway, showing 
manner of anchoring frames to the vertical reinfor- 
cing, and position of plank doors. 

the concrete from sticking. This treatment is especially important 
where forms have wooden surfaces, but is also beneficial when applied 
to galvanized iron surfaces. 

Doorways 

Continuous and non-continuous doorways are used about equally 
in monolithic silo construction and the question of which to use is 
generally settled by personal choice. The continuous doorway has 
the advantage of providing a larger space through which to throw 
the silage and for this reason is preferred by many. The non- 
continuous doorways, as used by some of the best contractors, have 
no disadvantage except they provide a smaller space through which 
to remove the silage. 

Continuous Doorways: — The best kind of a continuous doorway 
can be made by using two 4-inch Si^-pound steel channels, of a length 
1 foot greater than the distance from the floor of the barn to the top 
of the silo. Holes large enough to receive ^-inch rods must be 



UNIVERSAL PORTLAND CEMENT CO. 



47 



drilled in both channels in the same relative position at intervals of 
12 inches. Through these the ^-inch stay rods are placed as shown 
in Figure 33 Between each stay rod hole in each channel, a hole 
is drilled to receive the >4-inch hooked bolts, which are fastened to 
the vertical reinforcing rods, adjacent to the doorway. 

Frames and Doors: — Before commencing work on the silo walls, 
the channel for the door frame should be drilled as shown in Figure 
34 and the frame assembled by means of the bolts. 

It will probably be found convenient to order the channels and 
rods from the local blacksmith, who has facilities for drilling the holes 
in the channels and threading the rods as required. The door frame 
may then be broug-ht on the job ready to be 
assembled. The doors should also be made 
before the wall is commenced. These con- 
sist simply of 2x1 2-inch plank planed on both 
sides, 34 inches long", with |-inch holes drilled 
through the center to accommodate the bolt 
and hook by which the door is held to the i- 
inch bolt in the frame. The bolt in the cen- 
ter of each door has a screw eye on the outer 
side on which hangs a common gate hook. 
(See Figure 33). The doors are given a slight 
taper all around towards the outside. 

Erecting and Anchoring Door Frames : — 
As soon as the silo wall has been brought up 
to within 1 foot of the level of the barn floor, 
the door frame is raised to the position it is to 
occupy in the silo and held securely in place 
by means of wooden bracing and guy ropes. 
The wall is then continued up to the level of 
the barn floor. 

In the case of tall silos, where the steel 
frames have to be made in two or more sec- 
tions, it will be found convenient to put in 
only one section at a time. The sections may 
be joined together with splice plates. Five 
or six of the wooden doors should be painted 
with crude oil and then put on and the con- 
creting resumed. 

These doors are placed in position for the 
purpose of keeping the concrete from running 
around the steel frames on the inner side of 
the wall, which would otherwise be possible 
since the distance between the inner and outer 
forms is 6 inches and the wid.-i of the frame but 4 inches. After 
the work has proceeded upwards a short distance some of the lowest 
doors may be removed, taking care not to knock off corners of 






Tl" 



i»i 



n 

h! 
hi 

-ul 

ii 

I I 

i! 

Uj. 



r 



^gA.Bf-i TlOOW 



Figure 34. Spacing of holes in 
Steel Channel Side Frame for 
continuous door openings. 



48 



CONCRETE SILOS 




Fig. 35. Wooden form for a non-continuous 
doorway and steel frame made of angle iron. 



^""^"^^^ green concrete. These doors 
ma}^ then be replaced on the 
frame at a point above the 
forms. 

Non-continuous doors: — Non- 
continuous doors are perhaps 
easier to build than continuous 
doorways, and if the owners are 
satisfied that they provide suffi- 
cient room for getting the silage 
out conveniently, there is no 
objection to their use, although 
on the other hand, they possess 
no great advantage over doors 
of the continuous type. The 
arguments often heard that 
the non-continuous door silo is 
a stronger type than the other, 
and vice versa, carry little 
weight, as either type may be 
made sufficiently strong. 

Non-continuous doors are often 
put in with a distance of aboiit 
2^ feet between them, but the spacing may vary to suit the indi- 
vidual owner. In all cases the arches between the doors must contain 
an amount of reinforcing equivalent to the full amount of horizontal 
reinforcing put around the silo. Thus, if the doors are 3 feet in 
height, with a distance of 2^/2 feet between them, the horizontal 
reinforcing in the space between the doors should be equivalent in 
amount to that i)]aced in 5^^ j feet of the wall where there are no doors. 

Doorway Form and Frame: Figure 35 shows a form for a non- 
continuous door opening. The bottom and top pieces are made of 
2x6" plank cut to the arc of a circle with diameter the same as the 
outer diameter of the silo wall. The two sides are made of two-by- 
fours. A frame of lighter material is placed around the outside of 
the form for the purpose of making a recess two inches deep around 
the opening on the inner side of the wall, into \vhich the door will fit. 
This frame is tapered to permit removal from the wall as soon as the 
concrete has hardened. It may then be used again for the next door- 
way above. 

If desired, a door frame of small angle iron (as shown) may 
be used to protect the corners of the concrete. The frame should 
be slipped on over the form, and both frame and form then placed 
in position. The angle iron should be cut a few inches longer than 
the dimensions of the opening and the ends embedded in the con- 
crete. The frame should also be anchored to the concrete by large 
spikes. Holes to receive the spikes should be drilled in the angles, 
12 inches apart. The spikes should be bent at right angles to secure 
a better hold in the wall. 



UNIVERSAL PORTLAND CEMENT CO. 



49 




Figure 36, Non-continuous Door, made of double 
layers of flooring with building paper between. 

Doors : — The doors may best be made of two thicknesses of 1x6" 
matched flooring with a layer of tar paper between. The 1x6" boards 
are held together by two 1x4" cleats across the top and bottom, and 
one 2x4" cleat across the center. The middle cleat is made larger than 
the others in order to take care of the strain caused by the large bolt 
in the center. A two-by-four, 40 inches long, or a similar piece of 
material, is placed on the bolt, making a large "])utton" by which the 
door is held to the wall. The door is clearly shown in Figure 36. 




Fig. .^7. Twin Silos of Mr. M. S. Dauberman. Big Rock, Iliiiioi- i > oiu n-ii' 

the other of monoHthic conS^rud:ion. Both are economical and keep iilaye i)erfectly. 



50 



CONCRETE SILOS 



Constructing Monolithic Silo Walls 

As soon as the foundation has hardened sufficiently to allow 
the work to proceed, the wall forms may be placed in position. 
Much care should be taken to locate them centrally and in 
such a manner that the sides are perpendicular. The 4x4-inch up- 
rights should be carefully put in position at this time, being sup- 
ported on wooden blocks or flat 
stones. After the inner form is in 
position, but before the outer form 
is placed, the horizontal reinforcing 
rods for the first three feet of wall 
should be wired to the vertical rods 
which were placed in foundation as 
previously mentioned. The outer 
forms should then be placed in po- 
sition and tightened, with the small 
wooden spacers in place. Before 
placing the concrete, it will be nec- 
essary to clean ofif the surface of the 
fmindation and moisten it thorough- 
ly. The wall forms, having been 
previously painted with crude oil or 
whitewash to prevent sticking, may 
then be filled with slushy concrete 
made in the proportion of one sack 
"f Portland Cement to two and one- 
iialf cubic feet of coarse sand, to 
iwur cubic feet of screened gravel or 
crushed stone, all of the latter be- 
ing between ^ inch and lYi inch in 
size. 




Fig. 38. K.N. Ouimhys silo. Batavia, Mich 
Built by R. t:. AiiKovinc, Coldwater. Ca- 
pacity. 90 tons; height, 36 feet. 



During the Summer 24 hours is usually enough for concrete to 
harden before raising the forms, but in cool weather a longer time 
will be required. If the work be undertaken while there is danger 
of freezing, the usual cold weather precautions must be observed. 
In such cases the materials should be heated, or at least free from 
frost, and mixed with hot water. The work in the forms must be 
protected for several days wath manure, straw or a canvas jacket 
under which live steam is run. 

Tables of Materials: — Table I show^s the approximate number 
of cubic yards of concrete required for the walls of monolithic silos 
of various sizes, with continuous doors, and w^alls 6 inches thick. 
Table J shows the quantities of cement, sand and gravel or stone 
required for silo walls, using proportions of 1 sack of cement to 2^ 
cubic feet of sand and 4 cubic feet of screened gravel or stone. It 
can hardly be expected that these tables will be exact in all cases, as 



UNIVERSAL PORTLAND CEMENT CO. 



51 



TABLE I 

CUBIC YARDS OF CONCRETE. 

Required for walls of Monolithic Silos with continuous doors. 

Walls 6 Inches Thick. 



Height 




INSIDE DIAMETER OF 


SILO. 






of silo 


















in feet 


8 ft. 


1 10 ft. 


1 12 ft. 


1 14 ft. 


16 ft. 


18 ft. 


20 ft. 


22 ft 


20 


9.0 


11.4 


13.7 


16.2 


18.3 








22 


9.9 


12.6 


15.0 


17.8 


20.0 


22.8 






24 


10.8 


13.8 


16.4 


19.4 


22.0 


25.0 


27.7 




26 


11.7 


15.0 


17.8 


21.0 


23.7 


27.0 


30.0 




28 


12.6 


16.0 


19.0 


22.6 


25.5 


29.0 


32.1 


35^6 


30 


13.5 


17.2 


20.6 


24.1 


27.5 


31.0 


34.5 


38.3 


32 


14.4 


18.3 


21.9 


25.8 


29.0 


33.1 


36.8 


40.8 


34 


15.3 


19.5 


23.2 


27.5 


31.0 


35.1 


39.0 


43.1 


36 


16.2 


20.6 


24.5 


29.0 


32.9 


37.2 


41.2 


46.0 


38 


17.1 


21.8 


26.0 


30.8 


34.8 


39.4 


43.6 


48.4 


40 


18.0 


22.8 


27.2 


32.0 


36.4 


41.2 


46.0 


51.2 


42 




24.0 


28.7 


34.0 


38.4 


43.4 


48.3 


53.5 


44 






30.0 


35.6 


40.0 


46.8 


51.0 


56.5 


46 








37.1 


42.0 


47.8 


53.0 


58.5 


48 










43.9 


50.0 


55.0 


61.5 


50 












51.5 


57.5 


64.0 



the difference in sand and gravel used, as well as other considera- 
tions, aft'ect the quantities of materials to a consi(lera])le extent. 
These tables are accurate to within 10 per cent. 

Moving up Forms for the Next Course: — To release the inner 
form, drive out the keys and if need be. remove a few of the bolts. 
Slide up the inner form on the upright supports and secure in the 
new position by the bolts passed through the supports just below the 
form, as previously explained. The 
inner form will then be bolted to- 
gether again and the keys driven 
into place. After attaching hori- 
zontal reinforcing rods to the ver- 
tical rods for the second course, the 
bolts in the outer form are loosened 
and the form raised by means of 
ropes attached to wire handles and 
running over the little brackets on 
the uprights. When the outer form 
is raised to a position flush with the 
inner form, the lower bolt should be 
tightened until the form presses 
snugly against the wall ; spacers 
should then be placed between the 
forms and the remaining two bolts 
tightened until the proper spacing 
is secured. The forms are then 
ready for the next filling. 




M 



Fi« V> I will tnoiiolithic silos, built by J. 
H. Mc(>o>, of H.jrnshiirsi, Pa., on the farm 
of Professor F. R. Lilly, near Wheeling, III. 
Both silos are 18 feet in diameter, and have 
a height of about 42 feet and a combined ca- 
pacity of 500 tons. The walls are 7 inches 
thick. 



52 



CONCRETE SILOS 



c p =-' 



" 5 



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a' <D 
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5| 

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si 

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o 


. . . .-^.lOtOlOOt-OrH^Ointe 




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2 2.8 
24.8 

28.5 
30.3 
32.0 
34.0 
35.9 
38.0 
40.0 
41.8 
43.5 
45.0 
47.2 




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:oodcjTt<Lr5i:-oioci^inooC5,-4Ci 

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S 

Is 
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o 

00 

to 


18.1 
19.5 
20.7 
22.0 
23.4 
24.6 
26.1 
27.3 
28.8 
29.S 
31.4 
32.6 




14.1 

15.3 
16.4 
17.5 
18.7 
19.9 
21.0 
22.2 
23.6 
24.6 
26.0 
27.0 
28.0 
29.6 




11.6 
12.7 
13.7 
14.8 
15.8 
16.9 
17.9 
19.0 

li 

23.9 
24.4 

25.5 
26.3 




9.3 
10.2 
11.2 
12.1 
13.0 
14.0 
14.8 
15.8 
16.8 
17.8 
18.6 
19.5 
20.4 
21.4 
22.3 




Tj.003t-tOCOr-IOOOI:-M-05,H05 • • 




oo' Ci oi d ^ ci CO i< "* in to t- 00 CO . . 




oc-tOT-ic-i-ocjcoincoot-co • • • 




3 'Sd 


y: 






5.8 
6.5 

7.0 

8.2 
8.7 
9.4 
10.0 
10.5 
11.1 
11.6 
12.3 




-^sSdd:::!:?^:^ ; ; ; ; ; 




- 
o ,; 

"3 .S 

■■Z '- 

li 

.2 


o 

CO 


49.7 
53.5 
57.0 
60.0 
64.2 
67.5 
71.3 
74.6 
78.7 
81.6 
85.7 
89.0 




38.5 
41.8 
44.9 
48.0 
51.4 
54.3 
57.5 
60.8 
64.0 
67.5 
71.0 
74.0 
76.6 
80.0 




32.0 
35.0 
37.8 
40.6 
43.4 
46.0 
49.0 
52.0 
55.0 
57.5 
60.5 
65.3 
66.5 
69.8 
71.6 




^oc^ou:>ci.-o-3-ooc^tot-ootoca • 




S ?^ S " « « S 5 !5 ^ S S S S S : 




tOO^COUOMOCO^OOLO'J'tOOO . • 




?3 5;?^S??"«S°^5:!*5E : : 




19.0 
21.0 
22.8 
24.8 
26.6 
28.8 
30.7 
32.3 
34.2 
36.2 
37.8 
40.0 
41.8 




16.0 
17.7 
19.2 
21.0 
22.3 
24.0 
25.7 
27.1 
28.7 
30.3 
31.7 
33.5 








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c^c^c^N<M«^5e<^coeo■<^..«.■*■♦■«l<lo 





UNIVERSAL PORTLAND CEMENT CO. 



53 







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54 



CONCRETE SILOS 



Joining Courses: — Immediately before the concrete is placed for 
each succeeding course, the surface of that previously laid should be 
thoroughly cleaned off and moistened, and coated with a cement and 
water grout of about the consistency of cream. This precaution is 
necessary to secure a good bond between the courses. It should be 
observed in all cases, as the pressure of the silage is apt to force 
moisture through any seams which might occur because of imperfect 
bond. Concreting should not be discontinued with a course partially 
completed, but if this is unavoidable the concrete surface should be 
left as nearly vertical as possible. 

Height of Wall at Each Filling: — Although the forms are made 
3 feet in height, the height of the wall built at each filling (after the 
first) will be 2 feet 6 inches, allowing the forms to cover 6 inches of 
finished wall when in position to be filled again. Experiment has 
shown that this is about the best height to fill at one time, as it 
makes about one-half day's work for the average farm crew when 
the mixing is done by hand. In reasonably good weather it should 
be possible for home labor to raise the forms each morning, refill 
in the forenoon and have the remainder of the day free for various 
farm duties. 

Labor Required: — The following estimate of labor required to 
construct monolithic silos is based on experience in a large number 
of cases, the materials being mixed by hand. The labor here given is 
approximate, and does not include that required to haul materials: 
Silos 8 feet in diameter 10 to 14 days (4 hours per day) 4 men 



10 to 16 
10 to 16 
10 to 20 
12 to 20 




Fig. 40. Simon Wierda silo, Zeeland, Mich., 
built of ornamental blocks with strap iron 
reinforcing placed on the outside. Capacity, 
26 tons; cost, $110. The blocks are solid and 
but 3 inches thick. This silo was built in 
1905, and although of exceptionally thin 
block, exhibits no cracks or other evidences 
of failure. 



" " " 4 to 5 men 

" " " " 5 men 

" " " " 5 men 

Reinforcing : — Steel rods are 
preferable to other kinds of reinfor- 
cing only because they come in 
standard sizes, the strength of 
which is definitely known. Any 
oilier kind of reinforcing, such as 
heavy wire fencing or other ma- 
terial of steel, having one section 
rigidly attached to another will 
do the work equally well, and 
may be successfully used if a suffi- 
cient quantity is put in to give a 
cross-section area equal to that of 
the rods recommended in table K. 
Spacing of Rods: — For all silos, 
regardless of diameter or height, the 
vertical reinforcing should be 
^^'^-inch round or twisted rods 
placed in the middle of the wall at 
intervals of about 3 feet. The size 
and spacing of the horizontal rein- 
forcing depends upon the diameter 



UNIVERSAL PORTLAND CEMENT CO. 



55 



of the silo and the distance from the top, and may be obtained for 
any given silo by referring to Table K. The first horizontal rods 
should be placed 2 inches above the foundation. Wherever rods are 
spliced, they must be lapped for a distance equal to 64 times the 
diameter, which is 16 inches for 34-inch rods, 24 inches for ^-inch 
rods and 32 inches for ^-^-inch rods. Immediately before the outer 
form is raised to position the horizontal rods should be wired in 
place for a distance equal to the height of the forms. The position 
of the reinforcing is very clearly shown in the sectional view, Figure 
61. Where a concrete cornice is put 
on an extra reinforcing band is put 
around the top for the purpose of 
strengthening it. 

Example : — Required, the proper 
spacing of horizontal reinforcing 
rods in a monolithic concrete silo 18 
feet in diameter and 44 feet in 
height. Referring to Table K, we 
run across the horizontal column at 
the top to "18 feet." Referring to 
the figures directly below we find 
that four sizes of rods may be used 
in reinforcing a silo of this diam- 
eter. The first four feet of the silo, 
i. e., starting 44 feet from the top 
and running to 40 feet from the top 
(see left hand vertical column) may 
be reinforced with ?,s-inch round 
rods 14 inches apart, ^-j-inch round 
rods 9 inches apart, or -^/s-inch round 
rods 5 inches apart, as shown in the 
columns under 18 feet, and parallel 
to 40 feet — 44 feet depth from top. 
Above this point the intervals be- 
tween reinforcing should be made 
larger, or a smaller size rod used, 
according to the table. Thus at the 
top of this silo, i. e., at a depth of 
0-4 feet from the top, the reinforc- 
ing should consist of 14-inch rods spaced 12 inches apart. Reinforc- 
ing rods are sold by weight, in stock lengths. One-fourth-inch rods 
weigh 16.84 lbs. per 100 feet; 3^-inch round rods 37.5 lbs. per 100 
feet; ^-inch rods 66.7 lbs. per 100 feet. 

Hoisting Materials: — The work of constructing the silo will be 
made much easier if a convenient method of hoisting materials is 
adopted at the start. The old scheme of raising the concrete by 
hand with a rope and a bucket wastes time and materials and means 
much unnecessary labor. Materials may best be raised with a rope 
and pulley, the latter attached either to a derrick frame, as shown in 




2:6'^ 3-0 

Figure 41. Convenient Derrick 
for hoisting materials. Design 
adopted from a similar one by the 
Iowa State College, Ames, Iowa. 



56 



CONCRETE SILOS 



Figure 41, or suspended from a frame resting on top of forms, the 
power in either case being furnished by a horse. The derrick shown 
in the figure may be built to any height required, in the following 
manner : Pieces marked "A" (2x6 inches, 16 feet long) are spliced 
together until a height at least 6 feet greater than that of the com- 
pleted walls is obtained. Pieces "B" (1x6 inches) are nailed to "A" in 
such a manner as to make an I-beam as shown in the sectional view in 
the center. The cross arm is made of a 2x6 inch piece 3 feet long 
spiked to piece '''A' and prevented from raising at the back end by 
piece "B" which runs flush with the top of the arm. The 
brace is made of 2x6 inch material, 3 feet 2 inches long. 
The three No. 9 guy wires are fastened to the cross arm and brought 
around in grooves provided for the purpose and fastened to stakes 
driven in the ground for a considerable distance from the bottom of 
the derrick. This device, which has been recommended by the Iowa 
Experiment Station, is said to have been tested and found safe for 
loads less than 400 pounds. 




Floor Line of Tank 



Fig. 42. Two monolithic concrete silos, built by the Polk- 
Genung-Polk Company for Mr. B. W. Lord, Danville, Ky. The 
right hand silo has a water supply tank 4 feet in depth on top. 
Both silos are 16 feet in diameter by 45 feet in height. 



UNIVERSAL PORTLAND CEMENT CO. 



57 



Commercial Monolithic Silo Systems 

SEVERAL very ins^-enious systems of silo forms have been de- 
vised and put into use in various parts of the country by silo 
contractors and construction companies. These are of a more 
substantial type than the home made forms and in most cases the 
same form may be used to build a great number of silos. Manu- 
facturers of these forms generally contract to build silos by their 
systems, but often sell the forms and territory rights or rent them 
to prospective builders for the job. A few of the best systems in use 
in the central part of this country are l)riefly described in the follow- 
ing paragraphs :* 

The Polk System: — This S3^stem. which is shown in its entirety 
in the illustration, Figure 43, is operated by the Polk-Genung--Polk 
Company of Fort Branch, Indiana, and a number of licensed con- 
tractors. The inner and outer forms are of heavy galvanized sheet 
iron, stifl'encd with angle iron. The}- are sus])ended by rods and 
chains from an iron collar which slides on a hollow steel mast. The 



r 



1 




Fig. 43. The Polk System in service, showing the patented metallic forms, method 
of raising and securing forms by the center mast, reinforcing metal, and appliance fcr 
hoisting materials. Two sections of the form are removed to permit a view within 
the silo. 



*It is hoped to give a more complete list in a future e 



dition. 



58 CONCRETE SILOS 

inner and outer forms are kept perpendicular and also held at proper 
distances apart by radial horizontal angle irons. These also serve to 
hold a platform. . 

One of the chief advantages of the Polk System is the method 
of elevating the concrete and depositing it within the forms. The 
apparatus consists of a steel bucket and cable, the latter running 
over a pulley attached to a trolley which travels on a steel boom. 
This boom is attached to the central mast by means of a collar which 
allows it to swing around in a full circle, .\fter it is filled with con- 
crete the bucket travels upwards until it reaches the trolley on the 
boom. The trolley is then released automatically and the bucket 
travels until directly over the forms. The trolley is prevented from 
going further by a' stop consisting of a steel pin placed through a 
hole^in the boom. Power for elevating the materials is generally 
supplied by a horse. The forms are raised in the following manner: 
A small flat collar is pinned in position to the mast about two feet 
below the collar which supports the forms. Two long jacks are then 
placed on the flat top of the lower collar in such a manner as to raise 
the upper collars when the jacks are operated. The mast is provided 
with holes a short distance apart to receive steel pins, and as soon 
as the jacks have been raised to their limit a pin is placed through 
the mast just below the upper cylindrical collar to prevent the form 
dropping while the jacks are being moved up to a new position. The 
forms must be loosened, of course, before any attempt is made to 
raise them with the jacks. 

The silos constructed by the Polk System have smgle walls six 
inches thick, reinforced with twisted steel rods 'A-inch to 5-^-inch 
in size. They are built with elliptical door openings, one door to 
every five feet in height. Except where especially desired by the 




Fig. 44. New Enterprise Concrete Machinery Company's silo form. The form for 
the round concrete chute, at the right of the illustration is worthy of special note. The 
form is made entirely of steel. 



UNIVERSAL PORTLAND CEMENT CO. 



59 



.>^^-, 



owner, roofs and chutes are not supplied. The former are considered 
unnecessary except in cold climates, and on most of the silos con- 
structed by this company the owners have used cheap chutes of 
wood. 

The Polk System is thoroughly protected by United States pat- 
ents. 

The New Enterprise System. — The New Enterprise forms, man- 
ufactured by the New Enterprise Concrete Machinery Company of 
Chicago, and used by the above company and a large number of silo 
contractors, are built of heavy gahanized sheet iron with angle 
iron stifTeners. Both inner and outer forms are built in sections 
which are coupled together with small steel pins or spikes. They 
are held at the proper distance apart by a steel frame which also 
supports a derrick. The materials are raised in a steel bucket, horse 
power being used. 

An interesting: feature of this 
system is the form of a semi-cir- 
cular chute. It is made of the same 
material as the silo form proper and 
with it the chute is run up at the 
same time as the silo. Reinforcing- 
used in both silo and chute consists of 
heavy bull fencing. Figure 44 shows 
the New Enterprise form as used for 
constructing silos with single walls. 
This form with the necessary modifi- 
cations is also used where it is 
desired to build the silo with double 
walls. In double wall silos the re- 
inforcing is placed in the inner wall, 
which is 4i inches thick. The outer 
wall is 4 inches thick and the air 
space between is 3 5 inches in width. 
Wall ties, made of gas pipe slotted at 
both ends, are placed between the 
walls in each course at intervals of 3 
feet, the slotted ends being bent so 
as to form, a crow foot. 

Although a large number of double wall silos have been con- 
structed in various parts of this country by this system, this com- 
pany considers double walls a precaution rather than an absolute 
necessity in localities where the climate is not severe. Both single 
and double wall systems of the New Enterprise Company are pro- 
tected by patents. 

Angevine System: — Mr. R. C. Angevine has built a large num- 
ber of "all concrete" silos in the State of Michigan, using for his 
purposes a system of wooden forms made of 1x6" wood facing at- 
tached to the ribs of heavy planking sawed on the arc of a circle. 
Each form is slightly more than 2>4 ^eet in height and two forms 



I 




[■iu.4,r Hollow wall coiKr.tc silo with con- 
crete roof, built for Edward Hoyt, Elborn, 
III., by the New Enterprise Machinery Co., 
of Chicago. 



60 



CONCRETE SILOS 



are used at the same time, one above the other. This makes it pos- 
sible for the work to proceed at the rate of 5 feet per day during good 
weather. The materials are hoisted on a small elevator with power 
furnished by a gasoline engine. 

Angevine silos have a foundation footing 30 inches in width 
g-enerally placed about 4 inches below the surface. The wall is put 
in 12 inches thick from the foot to grade, above which point the 
thickness is 6 inches. These silos are reinforced with heavy steel 
rods or cables spaced 1 foot apart uniformly. The size of the rods 
varies with the diameter of the silo and the distance from the top. 
liefore the walls have had time to dr}^ out they are finished off. both 
inside and out, with a coat of cement and water applied with a brush. 
The door openings are non-continuous, 24 inches wide by 32 inches 
high, and are sj)ace(l 2 feet apart. The doors are of galvanized sheet 
steel. 

The Angevine silos have reinforced concrete roofs, these being 
made 4 inches thick with a one-fourth pitch. The appearance is 
greatly improved l)y a wide cornice running around the base of the 
roof. Concrete chutes are recommended by Mr. Angevine and are 
put up wherever the owners desire them. 




Figure 46. C. A. Anderson's Silo Forms in use near St. Charles, Illinois. The 
platform on top of the inner Form is a great convenience. Materials are hoisted 
with the Elevator shown to the right. 

C. A. Anderson Forms: — Mr. C. A. Anderson of St. Charles, 111., 
has constructed about fifty silos in Kane and surrounding counties 
with the patented system of forms shown in Figure 46. The forms 
are made of heavy sheet iron braced with 2x4" wood studding and 
strengthened by strap iron hooks. The forms are raised by jack 



UNIVERSAL PORTLAND CEMENT CO. 



61 



screws. The materials are hoisted with the device shown to the 
right of the illustration. Mr. Anderson has made a number of im- 
provements on his forms this season, but pictures could not be se- 
cured in time for publication. 

McCoy Forms: — For a number of years Mr. John II. McCoy has 
been successfully using a system of forms of his own invention in 
the construction of large silos and railroad water tanks in many 
parts of the country. This system, which is now owned and used 
by the Steel Concrete Construction Company of Harrisville, Pa., is 




Fig. 47. McCoy's system of silo construction used by the Steel-Concrete Construc- 
tion Company, Harrisville, Pa. 

shown in Figure 47. The furms are of steel made in sections, each 
of which is supplied with a separate rig for hoisting. The materials 
are raised in steel buckets by horse power and deposited on a trough 
which travels around a circular track. This track makes it possible 
to move the trough to any part of the work that it is desired to fill. 




Fig. 48. View taken oil ,1 Wiscon, 
chief ration. Silo -.uRi harn ol H. M. 
pacity of silo, 110 tons ; cost, $17S.OO. 



\ 



4 



wM 



IS the 
Ca- 



CONCRETE SILOS 




Concrete Block Silos 

HOLLOW concrete block silos are popular in all of the northern 
states and more especially so in sections where the winters 
are extremely cold. In North Dakota and Minnesota there are 
scores of block silos in service, these being preferred to silos of any 
other construction, because of the security against freezing provided 

by the hollow wall. The cost of 
concrete block silos is often a trifle 
more than for those of monolithic 
construction, although this is not 
true in a great many cases. The 
best concrete block silos are those 
erected by contractors who have 
made a specialty of this class of 
work. Good block silos can be put 
up with home-made blocks and by 
hMiiie labor. Init where there is a 
reh'ablc block contractor in the vi- 
cinity it generally pays, in a saving 
of time as well as in numerous 
other ways, to have the work done 
by persons with previous expe- 
rience. 

Examining Blocks: — When the 
work is done by a contractor, the 
owner should take the precau- 
tion of examining the blocks which 
go into his silo^ rejecting those 
that are damaged or of an inferior quality. A crack of any size, or 
broken or crumbly edges, indicate a weakness in the block and make 
it unsuited for use. Blocks may be tested for their water resisting 
qualities by placing a small amount of water on the surface and 
observing whether this remains or is absorbed. A block which read- 
ily absorbs moisture is obviously unsuited for silo work, which 
dampness must not penetrate. Warped and distorted blocks should 
be discarded because of their unsightly appearance. 

Laying the Blocks: — The foundation already described will give 
as good satisfaction for the block silo as for the monolithic (see 
pages 36 and 37 and Figure 25). The top of the footing must be 
made perfectly level, being tested frequently with a level iDoard. As 
soon as the footing has sufificiently hardened, the top should then 
be cleaned off and moistened and a coat of slushy mortar % inch 
thick put on. The first band of reinforcing should then be put in, 
and the first row of block laid on this mortar, beginning the blocks 
at the two ends of the wall next to the doorway and continuing 
around. The blocks may be more conveniently set in a true circle 
if a sweep similar to the one used in laying out the foundation is 
used here. Should the blocks fail to meet exactly, the circle should 



Fig. 49. A concrete block silo of pleasing 
appearance on the farm of Mr. Fred Ludt- 
ke, near East Troy, Wis. The concrete 
block chute is a great advantage, and was 
put on at a slight additional expense. The 
cost of the silo complete was $300. The 
owner does not consider a roof necessary. 



UNIVERSAL PORTLAND CEMENT CO. 



6^ 




be enlarged or made a little smaller, whichever happens to be the 
more convenient. A guide board with a convex curved edge, cut on a 
circle of the same diameter as the inside of the silo, should then be 
made and used in place of, or in conjunction with, the sweep in laying 
up the remaining courses. 

The Mortar: — The mortar 
should consist of one sack of Port- 
land cement to 2 cubic feet of 
coarse sand, with the possible addi- 
tion of a small quantity of lime (not 
over 10 per cent) if need be to make 
it easier to work. Before laying up 
the block see that they are thor- 
oughly sprinkled, which will pre- 
vent them from drawing moisture 
from the mortar. No more mortar 
should be mixed at one time than 
can be used up within 30 minutes 
after first moistening. If lime is 
used it must be thoroughly slaked. 

Reinforcing: — The only faihues 
reported on block silos have been 
due to a lack of sufficient reinforc- 
ing, caused in most cases by the 
overconfidence of the builder in 
the strength of the blocks, or fail- 
ure to realize the enormous outward 
pressure of the silage. Horizontal 
reinforcing is of the most impor- 
tance and must not be overlooked, 
silos is not considered necessary. Table M shows the size of rod 
which should be placed between each row of block or in the groove 
in each row of block, if such a groove is provided. Reinforcing rods 
in block silos are not lapped in the ordinary fashion, but are anchored 
around a block as shown in Figure 51, or the ends are hooked to- 
gether. 

Example: — For illustration, let it be assumed that the proper 
method of reinforcing a sif 32 feet in height and 16 feet in diameter 
is desired, blocks 8 "inches in height being used. Referring" to table 
M, pag-e 65, we run down the vertical column at the left until the 
figures indicating the greatest depth of the silo are reached. In this 
case these figures are "28-32 ft." Running directly across horizon- 
tally to the "l6-foot diameter column, we find that the proper rem- 
forcing 28-32 feet from the top of the silo is one ^-inch rod between 
each course of block; following up directly the 16-foot diameter 
column, we find that ^-inch rods must be used between each course 
until a point 16 feet from the top is reached. From here up 14-mch 
rods are used until 8 feet from the top when No. 6 rods are sub- 
stituted. 




-' I 



Fig. .SO. Block silo on the farm ot Henrv 
Brown, near Llkhcrn Wis. Cap.K itv , 92 
tons. Cost. S42.'>, complete. Built by Rein- 
ert, Maiscli & Baumback, Lake Geneva, Wis. 



Vertical reinforcing in block 



64 



CONCRETE SILOS 



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UNIVERSAL PORTLAND CEMENT CO. 



65 



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66 



CONCRETE SILOS 



Recesses for Reinforcing Rod: — The reinforcing is commonly 
laid in the mortar between the conrses of block, the strength of the 
mortar and the downward pressure of the blocks above being de- 
pended upon to keep the rods in place under loaded conditions. In 
the best practice, however, blocks are used which have a recess in the 
top face deep enough to accommodate the reinforcing rod. Recesses 
are generally put about tw^o inches in from the outside of the block. 



^Mce^ TO :b£ 

TIL Leo IV, TH COMCKI^I 



^METHOD or flNCHOft"^!:' 




Figure 51. Continuous door openini* for concrete block silo. View shows the 
manner of fastening reinforcing rods to the door frames, also of anchoring rods around 
a block instead of lapping. 



Continuous Door Frames: — The frames for the continuous door- 
way are made in about the same manner as those placed in mono- 
lithic silos, as described on page 46. Two 6-inch 8-lb. channels of 



UNIVERSAL PORTLAND CEMENT CO. 



67 



a length equal to the distance be- 
tween the barn floor and the top of 
the silo are used. Holes to receive 
^-inch rods are drilled on the cen- 
ter line of the channel at intervals 
of 12 inches, and holes of sufficient 
size to accommodate the reinforcing 
rods are drilled on a line 2 inches 
from one edge of the channel at in- 
tervals equal to the height of the 
block, which in most cases is 8 
inches. The drilling should be done 
by the local blacksmith unless tlic 
farmer or builder has special equi])- 
ment for doing this work. Great 
care should be taken to get corre- 
sponding holes in the two channel^ 
at exactly the same height and dis- 
tance from the edge. 

Bolts ^-inch in diameter and 2 
feet 6 inches long, threaded for 4 
inches on each end, should also be 
ordered from the blacksmith or 
made at home from ^-inch steel 
rod. Four nuts should be provided 
for each bolt. In assembling- the 
frame one nut will be placed on each 
end of each rod 2 feet 2 inches apart. 
into the f-inch holes in the channel, and the other nuts put on, which 
will hold the channel and bolts ti,^htl\- in place. The door-frame is 
then ready to be erected. The frame should be well braced until the 
walls are up far enough to hold it securely. 

As the reinforcing rods are laid upon successive courses of 
blocks, they are cut ofif long enough so that the ends will extend 
about one inch when brought through the channel. After being 
threaded the ends of the rod will be brought through the holes, 
drilled to receive them, and the nuts will be put on, but not tightened 
sufficiently to disturb the rods in case they are laid in the mortar 
and not in recesses in the blocks. 

The doors should be made of 2x12" material in the same manner 
as those for monolithic silos as described on page 46 and shown in 
Fig. 33. 




Fig. 52. Concrete block silo of Mr. J. W. 
Cooper, Whitewater. Wisconsin, built by 
the Charles B. Hurst Company, Chicago. 

The bolts will then be slipped 



68 



CONCRETE SILOS 



Home-Made Blocks 



A NUMBER of farmers in various parts of the country have put 
up concrete block silos of blocks made during spare time with 
a block machine or a home-made mold. Good blocks can be 
made by either method, but the use of a machine quickens the work, 
and does it in a more uniform manner with the expenditure of a great 
deal less labor. 

Block Machine Manufacturers:— For the benefit of those who 
may wish to manufacture silo blocks with a machine designed for 
the purpose, the following list of manufacturers, who exhibited their 
machines at the Chicago Cement Show, is given. There are also a 
large number of other machines on the market capable of making 
good silo blocks. Any of the following will be glad to send full 
information regarding their machines on request: 

The American Hydraulic Stone Co., Chicag-o. 

The Anchor Concrete Stone Co., Rock Rapids, Iowa. 

Ashland Steel Range & Mfg. Co., Ashland. Ohio. 

Cement Machinery Co.. Jackson, Mich. 

Century Cement Machine Co., Rochester, N. Y. 

Hayden Automatic Block Machine Co., Columbus. Ohio. 

Hobbs Concrete Machinery Co., Detroit, Mich. 

Ideal Concrete Machinery' Co., South Bend, Ind. 

Inman Concrete Block Machine Co., Beloit, 'Wis. 

Marsh Co., Old Colony Bldg., Chicago. 

Miles Manufacturing Co., Jackson, Mich. 

Multiplex Concrete Machinery Co.. Elmore, Ohio. 

Somers Bros. Manufacturing Co., Urbana, 111. 

U. S. Gas Machine Co., Muskegon, Mich. 




Figure. 53. Home-MaJe Silo block mold. 



UNIVERSAL PORTLAND CEMENT CO. 



69 



Home-made Molds: — The mold shown in Figure 51 is a modifi- 
cation of that used by Wm. Stoll of Lansing, Mich., to construct 
blocks for his silo during the summer of 1907. It can be used to 
make blocks of any length up to 24 inches and of any width up to 8 
inches. The height of the blocks may be 8 inches or less. The mold 
can be made from a piece of old railroad tie 30 inches long, 8 inches 
wide and 6>^ inches high sawed on the arc of a circle, with a diameter 
4 inches greater than that of the inside of the silo. One-half-inch 
holes are drilled V/z inches from each end to receive 18-inch bolts, 
by which the sides of the mold are held at the desired distance apart. 
The end pieces are made of 1-inch planed lumber and have tapered 
wooden blocks 8 inches long, 5 inches wide and %-inch thick screwed 
to them for the purpose of making end cores on the blocks. The 
end pieces are held in place by wedge-shaped wooden blocks inserted 
between them and the bolts. If hollow blocks are desired, the air 
spaces may be provided by cores made of tapered 4x4" pieces. The 
inside of the mold should be well greased before use to prevent the 
concrete from sticking. 

Size of Block: — Although concrete blocks are made in a large 
variety of sizes, those most commonly used in silo work are 8 inches 
high, 8 inches thick and either 16 or 24 inches long, with half and 
quarter lengths as required. Blocks of these sizes are recommended 
as preferable to those less than 8 inches in height which require more 
labor to lay, or blocks more than 8 inches in height which are un- 
handy because of their weight. 



r 




Fig. 54. Concrete silo and dairy barn, University ut iSebraska Agricultural School, 
Lincoln, Neb. Construction of this type is frequent among the state agricultural 
colleges ; fully a score have concrete silos, 



70 CONCRETE SILOS 



Commercial Concrete Block Silos 

THE PERFECT SILO:— The Perfect Silo, built by the Perfect 
Reinforced Silo & Cistern Block Company, of Delaware, Ohio, 
has met with great favor amongst Ohio farmers and a large 
number have been put up in Delaware and adjacent counties. Some 
of these silos have been built by the owners with block purchased 
from the above company. 

This system differs from all others in the dimensions of the 
l)locks and the method of reinforcing. The blocks are made on an 
arc, 24 inches long, 12 inches high, and 4 inches thick. Each block 
is reinforced with two iron bands running lengthwise 6 inches apart. 
Each rod is looped and turned 6 inches from each end. These loops 
are spaced so as to correspond with ^-inch round vertical holes 
which are formed in the block. When the blocks are laid in the wall 
these vertical openings are filled witli cement and water grout and 
steel dowel pins are passed through this soft material and inserted 
about half \vay in the block below. The rods should be of such length 
that they will reach up about half way in the blocks above. The 
blocks have a groove Yj. inch deep in the top edge which provides 
space for a larger mortar bed and also for the heav}^ horizontal rods 
which span the Cdnliiuious door o])cnings at intervals of 2 feet. These 
rods are firmly fastened to the vertical dowel pins. The dowels next 




\JELKE DAIRY FAR 
., GOOD LUCK BUTTERINE 



ms^ 




mm ' m 



Fig. 55. Two larj^e monolithic silos on the .lelke Dairy Farm, Dundee, 111. The 
combined capacity of both silos is nearly 600 tons. The silo on the left was built by 
a contractor, and that on the right by farm labor under the direction of Mr. W. A. 
Dickinson, the farm superintendent. Both silos have concrete roofs. 



UNIVERSAL PORTLAND CEMENT CO. 



71 



to the door openings are made of heavy pipe in 4-foot sections firmly 
screwed together. 

This system is shown in Figures 56 and 57. 




Fig. 56. Detail of Lateral and Perpendicular Reinforcing in the Perfect Silo. 




Fig. 57. Sect 
Reinforcing co 



ional View showing Construction of the Perfect Silo and Method of 
ntinuous Doorway. 



72 



CONCRETE SILOS 



The Zeeland Silo: — A very interesting type of concrete block silo 
is being used extensively through the region between Holland and 
Grand Rapids, Michigan, which is known as the Zeeland silo and 
has been built exclusively by Mr. Chris Dejonge, of Zeeland, Mich. 

About 30 Zeeland silos have been put up by him in Ottawa 
County alone. The Zeeland silo has a number of unique features. 
It is the only silo of its kind using solid blocks made "tongue and 
groove" so as to fit any diameter of silo. The blocks are made 24 
inches long and 8 inches high and have a thickness of only 3 inches. 
They are laid up in 1:2 cement and sand mortar and the inside of 
the wall is plastered off with mortar of the same proportion. Rein- 
forcing consists of a heavy iron rod around each course, laid in a 
groove provided in the top of the blocks. Early silos of this type 
were reinforced with band-iron hoops 2 inches wide by ^ inch thick 
placed four courses apart. The silo of Mr. Simon Wierda shown on 
page 54 was the first one of this type constructed. 

Mr. Dejonge has lately (April, 1911) secured patents on a semi- 
circular steel chute and ladder which is placed on the inside of the 
silo. This permits the silo walls to be built up full all around, the only 
openini^' necessary being: a dcjor in the bottom. 

The chute is held to the silo wall by means of hoc^ks and eyelets, 
the latter being placed in the wall at the time of building. When 
it is desired to use off the silage, two top sections of the chute are 
removed, and as the height of the silage is lowered successive sec- 
tions are removed and hung two spaces higher. 




Fig. 58. Large nioiiolitliic silo, built bv Cornelius Aiiiire, Ciiaiulville. Michigan. 
Cost of materials, $82.00; cost of labor, $108.00; total cost of silo, $190.00. Mr. 
Andre has many creditable examples of concrete work about his place, includ- 
ing barn floor and dairy house. The silo shown above is admired by all of the 
fsrniers of the vicinity. 



UNIVERSAL PORTLAND CEMENT CO. 



73 




Concrete Chutes 

A PERMANENT chute of concrete is a valuable adjunct to any 
concrete or masonry silo. The same arguments presented for 
the concrete silo stand for the chute. The concrete chute is 
substantial and permanent, fireproof and cold-proof, and it greatly 
improves the appearance of the silo. 

Size of Chute: — Chutes in use 
in various parts of the country vary 
in size from 2 feet square to about 5 
feet square (inside dimensions), but 
the former size is much too small 
and the latter larger than need l)e. 
For the average monolithic silo a 
chute 3 feet by 4 feet in inside di- 
mensions is recommended. The 
outer dimensions will then be 4 feet 
by 4^ feet, the walls being 6 inches 
thick. A monolithic chute of this 
size will require one-third of a bar- 
rel of cement, }i, cubic yard of sand 
and 1/5 cubic yard of gravel, per 
foot of height. For the block siln, 
the size should be such as will hv 
accommodated by whole and half 
blocks. The outer dimensions of a 
hollow block chute (using 8x8x16" 
blocks) should be 4 feet 8 inches 
square, making the inside dimen- 
sions 3 feet 4 inches by 4 feet. This 
size will require 9j^ blocks for each 
course. 

Foundations: — The foundation 
for the chute should be 2 feet wide 
and 1 foot high, the same as that 
for the silo, using concrete of the 
same proportions. (See page 36.) 

built ^-inch vertical reinforcing rods must be imbedded in the foun- 
dation 18 inches apart. Monolithic chute walls may be built up 
simultaneously with the silo walls, but it is much more convenient 
to build them after the completion of the latter; chute walls of 
concrete block must be built at the same time, being built in and 
kept at the same level as the silo walls. 

Monolithic Chutes: — The accompanying illustration shows forms 
in position for building a monolithic chute. Two-inch planed lumber 
should be used for the face of the forms, and 2x4's for the vertical 
braces. The steel rods used to hold the forms together should be 
24 inches long, threaded for 4 inches at each end. Each section of 
the form should be about 2 feet (4 plank) high. To raise the forms 
the lower rods are withdrawn and the holes made by them cemented 




Fig. 59. 165-ton silo of A. R. McNeill, Wil- 
low Wall Poultry Farm, Old Fields, W. Va. 
Cost, complete with concrete chute, $405. 
Built by R. C. Angevine, Coldwater, Mich. 



If a monolithic chute is to be 



74 



CONCRETE SILOS 



up. The wooden braces are then raised, and the lower panels of 
planks placed above the others. 

The method of joining the chute to the silo is shown in the 
figure. Two 1x6" boards, with edges slightly beveled to permit of easy 
removal, are placed in a vertical position on the inside of the outer 
silo form, 3 inches to each side of the line of the doors. In this 
manner recesses "a" are produced. Three-eighths inch rods 30 
inches long, spaced at intervals of 18 inches, and bent as shown by 
the dotted lines in the figure, are used to hold the chute securely to 
the silo. The most convenient way to put in these rods is to have 
them lightly stapled to the boards occupying recesses "a." This will 
hold the rods in position until the concrete is placed. The forms 
and vertical boards may be moved as soon as the walls have hardened 
sufficiently, and the ends of the rods bent up into a horizontal posi- 
tion. Where windows are desired in the chute, the openings may be 
made with a form similar to that used for making non-continuous 
door openings, shown on page 48. 

The horizontal reinforcing of the chute should consist of 3.^-inch 
round reinforcing rods so spaced as to correspond with the rods 
binding the chute to the silo, so that they mav lap with the latter. 
The lap should be 24 inches long. Two horizontal rods should be 
placed over all windows. Short oblique rods, 24 inches long, should 
be put in about the corners of all windows, at an angle of 45 degrees, 
as a protection against diagonal cracks running from the corners of 
the windows. 

Block Chutes:— 
If the block silo and 
chute are put up si- 
multaneously the 
walls of the two will 
be held together by 
the blocks, and no 
reinforcing will be 
necessary. Window 
openings in the 
chute may be made 
by using concrete 
sills and lintels, 
which are easily ob- 
tainable from block 
dealers. A length of 
heavy strap iron may 
be substituted for a 
lintel, if desired, and 
the sill cast in place 
by means of a sim- 
ple box mold. 



Fig. 60. Forms for monolithic concrete chute. The illustration shows the recesses 
"a" and the ;H-inch re-inforcing rod used in joining the chute to the silo wall. 




UNIVERSAL PORTLAND CEMENT CO. 



75 




31CT/ON r/^/^OUG/i 5/LO 

61. Sectional view of a monolithic silo equipped with water supply tank, 



Fig 

roof and chute of concrete 



The small view shows section of the rectangular chute. 



76 



CONCRETE SiLOS 



Water Supply Tanks 

THE top of a monolithic silo is a convenient place for the farm 
water supply tank ; in fact, if one were about to build a large 
concrete tank, no better construction could be chosen than that 
of building- the base in the shape of a monolithic silo, whether it 
could be put to any other use or not. Where both silo and tank are 

necessities, as on large stock and 
dairy farms, the two may well be 
combined. 

Size of Tank: — Every farm 
should have a water supply tank 
large enuugli to take care of all the 
needs about the house and barn and 
still leave a reserve for use in case 
of fire. Table N shows the capaci- 
ties of tanks advocated for silos with 
diameters of from 8 to 16 feet, as- 
suming the tanks are filled to a 
height of five feet. It is hardly 
practical for inexperienced persons 
to build tanks of greater diameter 
than 16 feet, erected on top of silos, 
unless these tanks are especially de- 
signed for each particular silo. De- 
tailed plans of larger tanks will be 
designed by the Information Bu- 
reau, however, to fit individual 
cases and will be furnished upon re- 
quest. 

Planning for the Tank: — If a 
tank is to be built on top of the silo, 
due attentinn must be paid to this 
fact in planning the reinforcing for the walls. Thus, if it is desired to 
build a silo 40 feet in height with a tank 6 feet in height on top, the silo 
should be reinforced in the same manner as though it were 46 feet 
in height without any tank. From the floor of the tank to the top, 
the reinforcing will l)e put in according to the diagram on page 77. 

Bridging Across Continuous Doorways: — In silos with continu- 
ous doorways, it is necessar}- to bridge across the top of the door- 
way before laying the tank floor. The door-frame should extend 
up within one f(xjt of the bottom of the floor, and as soon as the 
walls have been built up to the level of the top of the frame, a rein- 
forced concrete beam 12 inches high and 4 inches wide should be 
put in, at least ojj feet long so as to give a bearing of one foot or 
more on each side of the opening. This beam should be reinforced 
with four i/^-inch round rods, and may be made in a small mold-box, 
without top or bottom. It should be placed in the inner side of the 
wall and the concreting then resumed up to the level of the tank 
floor. 




Fig. 62. Monolithic silo, built for the Agri- 
cultural Guild of the University of Chicago 
by J. H. McCoy (Steel Concrete Construc- 
tion Co., successors>, Harrisville, Pa. This 
silo is 47 feet in height, and contains a 250- 
barrel water tank within the top four feet. 



UNIVERSAL PORTLAND CEMENT CO. 



77 





TABLE N 






CAPACITY OF WATER 


SUPPLY TANKS 


* 


Diameter of 










tank in ft. 






barrels 




8 






()0 




10 






95 




12 






135 




14 






185 




16 






240 





"Depth of water — 5 feet. 
One l)an"el equals M.5 ,qal. or 4.21 en. ft. 

D I A M E T ]•: K <; F T A N K 



I Z K OF K () V N D 



i 

inch 



i 

inch 



inch 



ITt 



/Ft 



I 



I 3. 



fr. 



1 



.5 



1 






2rT. 



3rt 



5 Ft 



5 Ft 



SM 



\er^ 



78 



CONCRETE SILOS 



The Floor: — As soon as the wall has been brotight up to the 
level of the tank floor, the otiter form should be raised one foot and 
the inner form lowered one foot. A heavily braced platform which 
will support the concrete floor should then be erected upon the 
inner form. The floor form must be made of 2-inch planks sup- 
ported on 2x10 inch girders, braced 
to the staging as well as to the 
inner form, which must be 
strengthened if much of the weight 
of the floor is to rest upon it. The 
floor form must be able to support 

p- J a load exceeding 125 pounds to the 

r-- I s(iuare foot in the case of a 16-foot 

I silo, or 75 pounds to the square 

P! foot for an 8-foot silo. The great - 
— .^ est caution must be exercised in 
getting the framing put up in such 
manner that it will carry the load 
witliout danger of collapse. 
The entire hoor must be con- 
hj. _.. , cretcd at one operation. The 
^'^- '^ necessary materials must be on 
hand, and provision made for mix- 
ing in large batches and elevating 
as speedily as possible. These are 
points which are absolutely essen- 
tial for perfect work. The con- 
crete should be made in the propor- 
tion of one sack of cement to 
23^ parts clean, coarse sand, and 4 parts of screened gravel, the 
latter to contain no particles smaller than }i inch. The concrete 
must be thoroughly mixed with water enougli to flow with slight 
agitation. The following table shows the thickness of floor, amount 
and spacing of reinforcing and the amount of materials needed for 
tank floors of various sizes : 



Fig. 63. 14'j X i2 foot concrete block silo on 
the farm of Ed. Bellmes, Fond du Lac. 
Wisconsin. Built of "Wisconsin Pride" 
continuous air space blocks, by J. J. 
Coyne, Fond du Lac. Wisconsin. Cost 
complete, $275M). 



TABLE O. 
MATERIALS AND REINFORCING FOR TANK FLOORS 



tank 

IN FEET 


Total 

thickness 

of 

floor 


Cement 
req'd. 
bbls. 


Sand 

req'd. 

cu. 

yds. 


Gravel 

req'd. 

cu. 

yds. 


Pounds of 1 
inch round 

rods req'd. 


Pounds of i 
inch round 
reinforcing 
rods req'd. 


No. of 
lengtns 


Spacing of 
reinforcing 

rods 
(inch, apart) 


8 
10 
12 
14 
16 


6 in. 

7 " 
8/2 " 

10 " 
10 " 


1.3 
2.4 
4.2 
6.7 

8.7 


.48 

.87 
1.52 
2.42 
3.17 


.77 

1.4 
2.5 
3.9 

5.1 


96 
193 


... 

407 
492 

685 


16-16' 
32-16' 
38-16' 
46-16' 
82-16' 


6 in. to 8 in. 

4 " « 8 " 

5 " " 8 " 
5 " "8 " 
4 " " 8 •' 



Before placing any of the concrete, reinforcing rods for the floor 
should be laid down upon the platform, as shown in Figure 64. 
Begin to lay the rods at the center, at the closest spacing showii in 
the table, then lay the reinaining rods running the same direction, 
working to the wall where the greatest spacing shown in the table 



UNIVERSAL PORTLAND CEMENT CO. 79 

may be used. The reinforcing should then be placed in the other 
direction in the same manner, and wired at intervals of 2 or 3 feet 
with ordinary hay-baling wire. The ends of the reinforcing should 
be long enough to extend up into the wall at least two feet, being 
joined to the horizontal wall reinforcing. 

The reinforcing should be supported about an inch above the 
platform, on small cubes of concrete or strips of wood placed about 
2 feet apart, 1:3 cement and sand mortar should then be 
put on and worked under the reinforcing to a depth of about one 
inch, and the concrete immediately placed upon this. In case small 
wooden strips are used to support reinforcing, these may be with- 
drawn from the underside of the f^oor as soon as the framing is 
removed, and the resulting holes filled with mortar. Concrete cubes 
are preferable to wooden strips, and may be easily made in the fol- 
lowing manner: Lay down two 1-inch boards on a flat floor, one 
inch apart, and fill in the space between them with 1:3 mortar, 
trowelling off the top. The long strip of concrete thus formed may 
be broken up into short sections approximately cubical in shape. 

Continuing Walls: — After the floor has sufificiently hardened, 
the forms and scaffolding should be taken down, the wall forms 
hoisted up the outside, and placed in position on the tank floor. 





:^@SS[ffl 


fffft^f^ 


^ 




y^ 




ir I sl>\^ 




/ 




tjtr Ij 


rf r "^^^\ 




1^ 




rf ll 


ttl UUJ ^ 


/ 






T II 


I 1 1 


V 


\ 


//J 








jf ' 


^\ 


■ 


j{ 


^ = 




IH 


E 


\\ 


1 


II 


i 


■1 


N iiiiii 


^ 


1 


VvH 


~ "~ 


~ 






7 


V 


\ - 




— - ■ ■ ■ - - 




I, 


V 




<tN 








V 






--- : :II 


I '-'-itv 




4 


^:::: :::::t 








tMUt^ 



Fig. 64. Showing the method of placing reinforcing rods in the tank floor. 

Before concreting is continued on the walls, the surface must be 
cleaned off, thoroughly moistened, and painted with cement and 
water grout, mixed about as thick as cream. The concrete must 
then be placed before the grout shows any tendency to dry. Six 
feet will be found a convenient depth for the tank. 



80 



CONCRETE SILOS 



In large supply tanks, where the water is continually agitated, 
water seldom freezes sufficiently to damage the tank. However, it 
is much safer to build the tank »vith a slight batter all around, that 
is, making the inside diameter greater at the top than at the bottom. 
The inside line of the wall should slope outward one inch for every 
foot in height. Ice in forming expands and rises upward, and the 
batter thus relieves the pressure which would otherwise be commu- 
nicated to the walls, possibly injuring them, in the case of a hard 
freeze. 



Reinforcing: — The vertical reinforc- 
ing- above the tank floor is put in the 
same as below, with 2-inch rods, 
spaced at intervals of 3 feet around 
the circumference. The spacing- for 
the horizontal rods may be obtained 
from the diagram, on page 77. By re- 
ferring to the diagram, it will be 
seen that the vertical scale shows the 
distance from the top of the tank, 
each small division representing one 
inch. Across the top of the table 
are the tank diameters, running 
from 8 to 16 feet. The heavy black 
lines indicate the spacing of the rods. 
This diagram (page 77) may be 
conveniently used for tanks six feet 
deep or less. 




Fig. 65. Concrete block silo of C. D. Ames, 
Kaneville, 111. Diameter, 16 feet; height. 44 
feet. Built in 1910 from block manufactured 
by F. W. Merrill, Kane\ille. 



Example : — Suppose it is de- 
sired to know the proper reinforc- 
ing for a tank 14 feet in diameter and 6 feet deep (to hold 5 feet of 
water net). Running across the top horizontal column until 14 feet 
is reached, we find (directly below) that two sizes of rods — }i inch 
and yi inch — are used. Running to the bottom of the vertical dia- 
grams, it will be seen that a ^-inch rod is placed 2 inches from the 
floor line. The next two rods are also ^-inch, spaced 7 and 14 
inches above the first rod. Above this point ^^-inch rods may be 
used to the top, as shown, or three more ^-inch rods may be used, 
and the change made to j4-i"ch rods at a point 2 feet 5 inches from 
the top. 

Piping and Overflow: — The intake and outlet pipes should run 
up one corner of the chute, far enough from the wall so that they 
may be covered to prevent freezing. The overflow outlet may con- 
sist of a 3-inch pipe passing through the w^all about 6 inches below 
the cornice. This pipe may be run down within the chute or on the 
outside of the silo, and led to a line of tile. In many cases, how- 
ever, the pipe is simply made to stick straight out of the wall about 
a foot, and the overflow is not drained off in any way. This method 
is not recommended as a general thing, but may be suitable if close 
watch is kept so that the tank is rarely filled to the overflow point. 



UNIVERSAL PORTLAND CEMENT CO. 



81 



T 



The Concrete Roof 

HE functions of a roof on a silo are (1) to prevent the cold 
from reaching the silage and (2) to make it more convenient 
to work in the silo during stormy weather. Manv farmers 



roof necessary and in moderate 
agree, however, that in sections 




and contractors do not consider a 
climates this is probably so; all wil 
of the country where the tempera- 
ture goes below zero a roof is a 
positive necessity, as well as a great 
convenience under any circum- 
stances. 

The logical way to finish up a 
concrete silo is with a concrete roof. 
Of 110 concrete silos recently in- 
vestigated by this Company, 39 had 
concrete roofs, 30 wooden roofs, 3 
steel roofs, 13 had no roofs of any 
sort, and on 16 silos no note of the 
roof was made. Of the silos with 
concrete roofs, more than a majority 
were built during the last two years, 
showing that the tendency at the 
present time is toward the all-con- 
crete silo — from foundation to pin- 
nacle. If the directions given in the 
following paragraphs are closely 
followed, little difficulty will be 
found in putting on a good roof of 
concrete — one that will last in- 
definitely without need of being 
shingled or otherwise repaired, and 
which will be in no danger of blowing off. 

The Cornice : — A cornice is only necessary where a roof is to 
be put on, its chief uses being to prevent water from the roof from 
running down the walls, and to improve the appearance of the silo. 
Figure 67 illustrates how the forms are made for the cornice on a 
monolithic silo. 

The brackets for the forms are made of }i"x2" strap iron bent 
as shown, and drilled to receive three stove bolts. These brackets 
should be placed on the outer form at intervals of about 6 feet, 
holes being drilled at the proper points to receive the stove bolts. 
The bottom of the cornice mold box is made of 2"x6" planks in short 
lengths, sawed to the arc of a circle with diameter 1 foot larger than 
that of the inside of the silo. The side of the mold is made of 
l"x6'' planks spiked to the bottom boards. The mold is held in 
place by screws through the bracket, as shown. An extra band of 
horizontal reinforcing is put in the cornice, as may be seen in the 
figure. The vertical rods in the silo walls and the radial rods of the 
roof are all brought around the horizontal reinforcing in the cornice, 
thus holding it in place and strengthening the cornice. 



I-IK. '-'> lllll-loii K.ii. i.'lr l-.Ioik siloof.Iolin 
IU(ts,(,oiio\.i,\\ IS. Built hy owner ill 1909. 
Cost. $500.00, complete. Blocks are 20 in- 
ches long, 6 inches high, and 8 inches thick. 



82 



CONCRETE SILOS 




r Half round 



..^:)toi/e Bo/to 



For the top section of the wall (last filling of the forms) the 
inner and outer forms are brought up to the line of the top of the 
completed wall. The forms are then filled to within one foot of the 
top, the outer form removed, and brackets attached. (If the stove 
bolts are already in place the form need not be removed to attach 
the brackets). The mold box will then be put in place. The cor- 
nice will be concreted at the same time as the roof, as will be ex- 
plained later. 

Roof Framing : — The roof framing may consist of two-by-fours 
or similar material, resting on the top of the inner wall form as 
shown in the sectional view, and the lower left-hand quadrant of the 
plan view, Figure 68. In case of a silo with a water tank on top, 
the forms must be removed before the roof framing is put up, and 
the latter supported on a light framework erected within the tank. 

The roof frame may be boarded 
up as shown in the plan view, 
with boards running- either rad- 
ially or otherwise, as desired. 
, „ These boards should be placed 

^ X Z Brocket close tog-ether to prevent the 
concrete from coming through 
when placed upon them. Table 
P shows the vertical rise to 
be given to roofs for silos of 
various diameters. 

A hole about 2\ feet square 
must of course be left for filling 
the silo, or if a roof covers a 
tank the hole will afford access 
to the latter. Before placing 
the reinforcing or the concrete, 
the top of the framing should be 
covered with old newspaper, 
building paper, or similar ma- 
terial, which will prevent the 
concrete from sticking to the 
forms. This will greatly facil- 
itate their removal. 

Placing the Reinforcing: — The 

lower right hand quadrant of 
the plan and the sectional view 
show the spacing of the radial 
and hoop reinforcing. The 
former is placed so as to be one 

Box for Cornice ^^^^ ^P^^^ i'^ J^'^ circum- 

ference, and the latter so 
Fig. 67. Mold box for Silo Cornice that the distance between the 



formj in place for 
Top section and Cornice 




UNIVERSAL PORTLAND CEMENT CO. 



83 




Fig. 68. Reinforced concrete roof design. The wooden framing is 
removed as soon as the cover has become thoroughly hardened. 



84 



CONCRETE SILOS 




three bottom hoops is 6 inches, between the next three hoops 9 
inches, and between all remaining hoops 12 inches. Extra rods 
should be put in around the window opening if the regular rods do 
not follow the outline of the window closely enough to reinforce it. 
All intersections must be wired together, and the outer ends of the 
radial wires brought down and 
bent around the horizontal rein- 
forcing in the cornice, as shown. 
The reinforcing should be sup- 
ported one inch above the roof 
frame, so that when the concrete 
is put on, the rods will rest on a 
one-inch bed and be covered by 
a three-inch bed, the total thick- 
ness of the roofbcingfourinches. 
For amounts of reinforcing ne- 
cessary for roofs of various dia- 
meters, see table P. 

Concreting : — Concrete for 
the roof should be made in the 
proportion of one sack of cement 
to two cubic feet of coarse, clean 
sand, to three parts of screened 
gravel. The concrete should be 
mixed as wet as it can be put on 
without danger of running to 
the edges of the roof due to the 

pitch. The top should be trowelled off smooth, in the same 
manner as a sidewalk. Concreting should begin at the cornice working 
around tlie roof, so as to keep the concrete on all sides at an even 
height. As the work progresses toward the center a broad board, 
on which to stand, may be laid on the concrete already laid. It will 
also add greatly to the safety of the men working on the roof if a 
rope attached to the pinnacle is tied about the waist of each. In 
place of this, it is often desirable, for the sake of greater safety to 
the workmen, to put up a scafifolding on the outside of the silo. 
Special care must be taken to protect the roof from sun, strong wind 
and freezing until thoroughly hardened. For this purpose a cover- 
ing of straw, manure, or canvas is generally effective ; if either 
straw or manure is used it may be necessary to weight it down. 
The effect of sun and wind is to dry the concrete out too rapidly, 
causing checking and cracking; frost afifects the strength of the con- 
crete and is otherwise objectionable. 

Monolithic Roofs for Hollow Block Silos: — Where it is desired 
to put a monolithic concrete roof on a hollow block silo, the wall 
should be laid up in the usual manner until the third course of block 
irom the top is reached. The blocks used in this course should be 



Fig. 69. Block silo of Col. Fred E. Shubel. Syca- 
more Farm, Lansing, Midi. Diameter, 12 feet; 
height, .W feet. Cost, complete, about $180.00; 
capacity, 94 tons. Bevel faced blocks were 
used, and the inside finished with 1:2 cement 
and sand mortar. 



CONCRETE SILOS 



85 



TABLE P 

DIMENSIONS AND MATERIALS FOR ROOFS 

For Silos with Diameters 8 feet to 22 feet 





Vertical 
Rise 


Volume 

of 

concrete 

in cu. yards 


Cement 

required 

bbls. 


Saml 
required 
eu. yds. 


Stone 
required 
cu vds. 


\ Inch Reinforcing 


Rods 


eter 
of Silo 


No. of 
rods 


Stock 
length 


No. of 
pounds 












required 


of rods 


of rods 


8 ft. 


2 ft. 


0.63 


1.09 


0.33 


0.49 


26 


10 ft. 


42 


10 " 


2% " 


1.01 


1.75 


0.52 


0.78 


31 


12 " 


62 


12 " 


3 " 


1.49 


2.59 


0.77 


1.15 


33 


16 " 


88 


14 " 


"hYz " 


2.05 


3.56 


1.07 


1.58 


45 


16 " 


120 


16 " 


4 " 


2.71 


4.72 


1 41 


2.08 


87 


10 " 


146 


18 " 


4 " 


3.34 


5.80 


1.74 


2.57 


93 


12 " 


187 


20 " 


4 " 


4.11 


7.15 


2.13 


3.17 


107 


12 '^ 


226 


22 " 


4 " 


4.M3 


8.55 


2.56 


3.80 


113 


14 " 


2(.5 




solid, namely, made without cores, or if witli the cores these should 
he filled up with mortar. The last two courses of hollow block 
should then l)e laid, the cores being left open. 




Fig. 70. Cornice block for concrete block silo. 

Special cornice blocks should be cast to make the cornice pro- 
jection, and for this purpose a mold similar to that shown in Figure 
53 can be conveniently used. The block should be 14" in width and 
of the same length on the inside of the wall as the wall blocks. The 
portion of the cornice blocks directly above the wall blocks should 
be 6" thick, while the projecting ends of the blocks should be but 
5" thick, so as to give a one-inch drop. The roof framing is then 
put up in the same manner as described on page 82, but in this case 
it must be supported by the scaffolding instead of on the inner 
form mentioned there. The reinforcing is placed in the same man- 
ner as described on page 82 and shown in Figure 68, excepting that 
the outer ends of the radial rods are made to extend down through 
the holes in the block for a distance of a foot or more. Since the 
holes in the third course of block from the top were either omitted 
or filled up before these blocks were laid, holes in the two upper 
courses can be filled up with wet concrete as soon as the reinforcing 
rods are in position. The roof is concreted as described on page 84. 
Before the concrete is placed on the cornice blocks this must be 
moistened and painted with a cement and water grout. 



86 



CONCRETE SILOS 




Fig. 71. William Stoll's block silo, near Lan- 
sing, Mich. The blocks wore nnide by the 
owner upon the concrete floor of his d:iiry 
barn, and laid up a row at a time, as lie had 
an opportunity The estimateti cost was 
$1.^7.50 including labor; capacity 07 tons. One 
of the first concrete silos in Ingham county. 




Fig. 72. Mr. Frank Bennett's concrete block 
silo. East Troy. Wis. 8-in. by 8-in. by 20-in. 
rock face block were used, these being ob- 
tainetl from a local dealer. This silo holds 
1 1.< tons and cost S340. The roof is of sheet 
steel. The contractor was Albert F.lbert, of 
East Troy. 









Fig. 73. F. W. "m, , Crete block silo, 

Kaneville, 111. Maik- waii patented block 
manufactured by Mr. Merrill. Cost, $450- 
capacity. 160 tons. This silo was put up 
complete in 4 days. 



Fig. 74. C. Shaw's nx.i 
silo. New Augusta, liuii 



UNIVERSAL PORTLAND CE.MENT CO 87 



Booklets for Free Distribution, 



CEMENT DRAIN TILE. 

An illustrated thirty page booklet embracing the results of an in- 
vestigation into the durability of cement drain tile. 



CONCRETE SURFACES. 

A thirty-two page booklet describing various methods of concrete 
surface treatment with information as to cost and illustrating repre- 
sentative concrete surfaces in colors. 



CEMENT STUCCO. 

An illustrated pamphlet on cement stucco containing specifications 
and table of colors to be used in cement plaster. 



CONCRETE CHIMNEYS. 

A report of an investigation made by Sanford E. Thompson. 

CONCRETE POLES, 

A comprehensive discussion of the subject of reinforced concrete 
poles prepared by R. E. Coondjs and C. L. Slocum. 

CONCRETE PAVEMENTS. 

The history of their use in tliis country, their cost and construction, 
with specifications. 

PORTLAND CEMENT SIDEWALK CONSTRUCTION. 

By C. W. Boynton; sets forth the requirements for good concrete 

sidewalk construction and how to obtain the best results. It contains 

specifications for cement sidewalks and table of sidewalk practice 
in the principal cities 

CONCRETE IN THE COUNTRY. 

One hundred and twelve pages of.simjjle instructions for building 
farm structures of concrete. I 



MAY 15 (312 

88 CONCRETE SILOS 



Booklets for Free Distribution 

(Continued) 



STANDARD SPECIFICATIONS AND UNIFORM METHODS OF TEST- 
ING AND ANALYSIS FOR PORTLAND CEMENT. 

Embracing report of the Committee on Standard Specifications of 
the American Society for Testing Materials, the report of the Com- 
mittee on Uniform Tests of the American Society of Civil Engineers 
and the report of the Committee on Uniformity and Technical 
Analysis of the Society for Chemical Industry. 

THE MANUFACTURE OF UNIVERSAL PORTLAND CEMENT. 

A brief pamphlet descriptive of the process of manufacturing Uni- 
versal Cement. 

MONTHLY BULLETIN. 

A twenty page monthly periodical describing the more important 
work in which Universal Portland Cement is used, with announce- 
ments, notes and brief articles of timely interest. 

FARM CEMENT NEWS. 

A periodical on the use of cement for the progressive farmer. 

No. 3— "Selecting and Mixing IMaterials for Concrete." 

No. 4— "Concrete Walks and Floors." 

No. 5 — "Concrete Foundations." 

No. 6 — "Concrete Troughs and Tanks." 

No. 7- — "Concrete Line Fence Posts." 

No. 8 — "Concrete Corner and End Posts." 

No. 9 — "Concrete Building Blocks." 

No. 10— "Concrete Walls." 

CONCRETING IN COLD WEATHER. 

A study dl" niruK'rn oijuipment as used for the successful prosccutidu of 
ciiinrrtin,L^ ihrnuyh winter weather. 

PERMANENT PAVEMENT. 

A periodical devoted to the use of concrete in road construction. 

We maintain an Information Bureau for the purpose of assisting our friends 
and customers in new problems involving the use of concrete with which they 
may meet. Our advice and help is free for the asking and involves no obligation 
whatex'er. We will l)e glad to ha\'e you write us requesting infcTrmation about any 
point. Your incjuirx will receive our prompt attention. 

Write to the nearest ol¥ice of the 

Universal Portland Cement Co., 

Chica<^o Pittsburgh Minneapolis 

IZ West Adams St. p^i:ick Building Security Bank Bldg. 



LIBRftRY OF CONGRESS 

ilHIi 

002 766 091 5 



B\ PORTLAND 7rV 



Sampling UNIVERSAL 
Portland Cement four 

hundred and fifty times an hour as 
the finished product leaves the mill 
is one illustration of the thorough- 
ness and care exercised at every 
stage in its manufacture. Our 
method of obtaining fair samples 
by means of an automatic device 
which removes from the conveying 
belt entering the storage bins a 
certain quantity of cement every eight 
seconds, was originated and is employed 
exclusively by this Company. 

Universal Portland Cement Go. 

Chicago— Pittsburgh— Minneapolis 
PLANTS AT CHICAGO AND PITTSBURGH 



Annual Output 12,000,000 Barrels 



